Last time around, we introduced you to our Dart University series with a few topics that get a lot of play on the Dart Heads customer service help lines – block oiling, setting valvetrain geometry, and using stud girdles to stabilize the valvetrain in high-performance applications. In this installment, we’re going to take a look at prepping the block itself, the proper way to install head studs, and how to set valve lash, and once again we’ve got Dart’s Jack McInnis as our sherpa as we climb higher. McInnis and the whole Dart customer service team aren’t just there to help out big-shot internet superstars like us, though – their years of experience and invaluable advice are just a phone call away for anyone building an engine with their parts.

Block Preparation

Everything in a build starts with the block itself, so doing it right starts from this foundation. Dart offers their blocks with two levels of preparation, depending on whether you’d prefer to have the final touches done locally, or let Dart handle those details. A “standard” block will arrive with cylinders bored to spec, needing only a finish hone, and decks machined flat and parallel. “We leave the decks .005 to .008 tall for final finishing,” McInnis explained, “ but they don’t require any further machining unless a specific ‘zero deck’ condition is desired.” Another area where Dart leaves clearances tight is the lifter bores, allowing for final honing to get a perfect fit. “We do it this way because each manufacturer has their own specs and tolerances, so there is no ‘right’ one-size-fits-all dimension,” McInnis says. One typical block prep task, making room for the rods in a long-throw engine, is already taken care of by Dart. Per McInnis, “all Dart blocks are clearance for stroker cranks. The exact stroke that can be accommodated depends on the specific crank and rods used, and of course extra clearancing can be done.”

When you're deburring your new block, work carefully to avoid critical surfaces like the main bearing saddles and the cylinder walls.

Though the heavy lifting has already been done by Dart, there’s still an opportunity to spend some quality time with a die grinder and sanding roll on your new block, deburring all the non-critical surfaces to break the hard edges and remove any remaining casting flash. The process accomplishes several things – primarily getting rid of any burrs that might subsequently find their way into the oil, but don’t discount the value of eliminating sharp edges that might chew your hands up later in the assembly process. Steer well clear of machined areas like the main bores, deck, and cylinder walls, but McInnis does add, “When deburring, one thing people often overlook is the bottoms of the cylinder bores.” A gentle hand here is required, but it’s not difficult if you simply take your time and work carefully to avoid the cartridge roll getting away from you.

After deburring, a thorough cleaning to remove all traces of machining debris and cutting oil will ready your block for assembly.

With that accomplished, the final step is inspection and cleaning. “A thorough visual examination of the block is always advisable, checking all the threaded holes, oil passages, and so on,” says McInnis. Hot, soapy water and bottle brushes designed for engine builders are your friends here, knocking out any debris left in the oil galleries and removing traces of cutting oil left over from machining. Follow it up with some compressed air and a wipedown of the cylinder bores with lacquer thinner or a similar solvent to get them operating-room clean, then a final treatment with some light oil to displace any remaining moisture and prevent flash rust. One temptation to avoid, especially on used blocks, is cleaning up the threaded holes with a tap. Taps are designed to cut threads, not clean them, and the right tool for the job (if necessary) is a set of thread chasers, which will restore the threads without making them oversize like a tap will.

If all that sounds like a lot of work to do before you get to the fun of actually building your engine, Dart can also supply a fully-prepped block that’s bagged and ready to assemble right out of the box. You’ll need to supply more information on the front end, just like you’d have to do for your local machine shop with a standard block – “Lifter dimensions, special deck heights, the stroke and type of rods to be used,” per McInnis, plus what kind of cylinder finish you need for your chosen ring package. “There are a couple of ways we can deal with this,” McInnis explains. “It can either be a generalized spec, like an OE would do, or it can be quite specific if the customer wishes. In the latter case, we would require the specs from the manufacturers of your pistons and rings.”

Whether you’re getting a standard block or one that’s fully prepped, McInnis advises, “when the shipment arrives, look for obvious damage to the packaging which could have occurred during transport – it’s best to note this when the driver is still present in case there may be damage to the block.”

Tying it All Together

Moving on, we got an education on the fasteners that hold the major components together. In general, Dart recommends studs rather than bolts whenever possible for critical fasteners, for a lot of good reasons. A bolt puts its loads directly into the threads of the block, and any wear that occurs will happen on both the bolt and the block itself. A stud, on the other hand, threaded finger-tight into the block, puts its wear on its own threads and nut instead – a big advantage in block longevity for engines that will be assembled and disassembled on a regular basis. It’s a lot cheaper and easier to replace studs and nuts than fix a block with ruined threads.

Though they can make pulling a head with the engine installed more challenging, studs are preferred over bolts because they only have to deal with tension loads (rather than being simultaneously twisted, like a bolt) and they put the wear on the stud and nut threads, rather than on the threads in the block.

Because Dart uses blind-drilled holes, rather than ones that extend into the water jacket, you can also take advantage of a cool builder’s trick by using studs with a threadless “bullet” nose, or dropping a ball bearing into the bottom of the hole with a fully-threaded stud. When the stud is installed, instead of seating on the unthreaded shoulder of the stud, it will instead bottom out on the nose or ball, ensuring full thread engagement and putting the part of the stud in the block in compression rather than tension.

Because the threaded holes in Dart's block are blind-drilled and don't intrude into the water jacket, bullet-nosed studs (above) or standard studs with a ball bearing dropped into the hole (below) can be used instead of bottoming out the stud on the thread shoulder.

Whatever type of fastener is used, setting the proper torque is critical – everybody’s got their own pet assembly lube, but when it comes to bolts and studs, using the exact thread lubricant and torque method recommended by the manufacturer is mandatory. If parallel-ground washers are provided, use them; they’ll prevent friction between the nut and the surface being secured messing up the torque reading. Fastener quality and proper installation aren’t exactly ‘secrets’ of successful engine building, but it’s easy to be tempted to cut corners. Don’t risk losing a block just because you’re lazy or want to save a few bucks.

All Lashed Up

Setting valve lash is one of those tasks that requires a little finesse to do properly, but it’s a necessary step, both with a new build and for ongoing maintenance. Some slack is necessary to accommodate expansion as the engine warms up – a valvetrain screwed down tight when the engine is cold can hold the valves open a little when it’s up to temperature, so there has to be a provision for adjustment. With hydraulic lifters, oil pressure automatically takes up the slack, but mechanical (or “solid”) lifters require a tiny bit of lash, or free space between the nose of the rocker and the tip of the valvestem when the valves are at rest. With either type of lifter, the first step is putting the cam for the cylinder you’re working on to its “base circle”, the lowest point on the lobe. For milder cams, finding the base circle is as easy as getting the cylinder to top dead center on the compression stroke (both valves closed), then working your way around the firing order doing both intake and exhaust valves at the same time.

Setting the lash on a solid-lifter engine is best done with the engine up to operating temperature, but a cold lash to the proper specs will get you into the right ballpark.

Bigger, aggressive solid-roller cams can be a little more complex thanks to the fact that the lifters are on the base circle for such a short part of the camshaft’s rotation. To make absolutely sure you’re on it, simply turn the engine over by hand until you see the exhaust rocker for the cylinder you’re working on just start to come open. At that point, you’ll know for sure you’re on the base circle for that cylinder’s intake valve. Moving around the firing order, follow the same procedure and lash all the intake valves. Once they’re done, you can set the exhaust by going back to your first cylinder and bringing the intake valve all the way open, and just to the point where it begins closing again. You’ll be on the exhaust lobe’s base circle for that cylinder, and once again you can chase around the firing order to finish setting all the exhaust.

Setting the lash for a hydraulic cam is easy – put the lifter on the base circle and with the rocker backed all the way off, spin the pushrod between your fingertips as you tighten the adjuster. Once you feel resistance while you twirl the pushrod, another half to three-quarter turn on the nut will do it. This compresses the hydraulic lifter just enough to make sure it never tops all the way out in operation, while allowing it to work as it should. For solid lifters, get on the base circle and use a set of feeler gauges between the roller tip and the valve stem to adjust your lash to the recommended cold gap. That will get you into the ballpark, but for optimum performance and durability, you’ll want to “hot lash” the engine at operating temperature.
“The reason for hot lashing is that the heat causes everything to expand,” explains McInnis. “If you know the rate of expansion of your block and heads from experience, it is possible to set the lash tight when cold, based on that dimension subtracted from the recommended spec and be pretty close. Generally, though, it’s best to set lash at the recommended temp and specs.”

We’re just getting started with all the useful information Dart has at their disposal for the home builder, and if you’re craving more and can’t wait for the next installment in our series, check out their website at www.dartheads.com while we get it all together.

In general terms, big engines make big power! It stands to reason that if you want earth shaking, ground pounding power, you probably want to build a big block engine. Power, however, comes at a price. The old adage of “there’s no replacement for displacement” still holds true, but cubic inches of power doesn’t have to cost you cubic dollars. The high performance aftermarket has seen an influx of big block Chevy cylinder heads, many of which can fit into the tightest of budgets and still bring thundering punishment to the pavement.

When you are putting together the big block puzzle, one of the worse things you can do is buy whatever part is on sale this week. Randomly buying parts because they look good or because they have good street cred may cost you more in the long run. Big Block Chevy cylinder heads are a perfect example of where money spent wisely can pay off with some decent power without spending your kid’s entire college fund. Power does come at a price, but you can make some wise choices that produce the power you are expecting by picking up affordable heads.

With some smart shopping techniques, like knowing what your overall goal is, you can purchase a set of cylinder heads without breaking the bank, and more importantly, without compromising on power.  To help answer the question of “What cylinder head do I need for my big block Chevy?”we have assembled a guide that will help you get through the dense jungle growth of BBC cylinder head choices. Follow along as we go for a run through the jungle.

The Key to Finding the Right Cylinder Head

RHS’ Product Manager Kevin Feeney summed up the process of finding the right set of heads for your BBC, “The first step is to determine what you are trying to accomplish with the engine. Are you looking for torque or horsepower, or the best combination of them both? This and the size of the engine are vital to choosing the proper runner sizes, valve sizes and ports for the application.”

With so many variables, and so many choices, it’s easy to go down the wrong path or find a shortcut to less performance. “Too many times guys tend to buy cylinder heads based on high lift flow numbers that are easily achieved with large ports and valves, but do not necessarily provide them with the performance they are looking for,” added Feeney.

Cast Iron being poured into molds at the foundry. (Photo from CFM Corporation)

What this Guide Covers

Our comprehensive guide to budget-friendly big block cylinder heads is strictly limited to fully configured and assembled units that are sold as a set for under $2,000 and are perfect for street use. We limited the spectrum of head choices to engines that are designed to run 91 octane pump gas and are not trailer queens. If you’re building a car that you can’t drive to the track, you’re probably not looking for a budget friendly set of cylinder heads anyway and this guide won’t cover the range of cylinder heads that you are looking for.

Our Criteria for budget friendly:

• A fully configured and assembled set of cylinder heads
• Priced under $2,000
• Street or Street/Strip use
• Designed to run on pump gas
• Must be able to make more power than stock OEM cylinder heads

Take a look at the big picture before rushing out to buy the first set of BBC heads you see.

Factors To Consider

There are several factors to consider when selecting the right set of heads for your big block. Dart Machinery’s Advertising Director, Jack McInnis explained “The size of the engine, rpm range, camshaft, type of fuel, weight and gearing all factor in. Whether the car will be street driven 99% of the time, or if it will be primarily raced and driven on the street only occasionally will make a big difference in the choice as well.” Armed with McInnis’ warning to take a look at the whole picture, we have broken down some of the basic characteristics that you need to consider when selecting a budget big cube head.

Aluminum heads look great and have a lot of good things going for them, but are they right for you?

Aluminum VS. Cast Iron

Cast iron is pretty common to most of us because it has been around the longest. Cast iron is inexpensive when compared to aluminum and is strong and durable. There are hundreds of different cast iron alloys but the kind that is typically used in cylinder heads is a gray cast iron. Gray cast iron is generally about 92-percent iron, 3.4 percent carbon, 2.5 percent silicon and 1.8 percent manganese. Rated at a tensile strength around 25,000 psi and a hardness somewhere near 180 on the Brinnell scale, cast iron heads are heavier than aluminum heads and can weigh as much as 30 percent more.

Aluminum’s main advantage is its light weight. Aluminum also dissipates heat very quickly, which may or may not be an advantage, depending on what you are trying to achieve. To make horsepower, you want some heat to be retained in the combustion chamber without detonation or preignition, which makes aluminum a great choice.

We talked to Billy Briggs of Briggs Performance about aluminum heads. “About the only drawback with aluminum is the simple fact that the aluminum alloy itself only has a life span of so long, but the pros are still huge. Ease of repair, ease of machining, heat dissipation and lighter weight are just a few,” said Briggs.

Aluminum alloys have become much better in recent years and the problems associated with heat warping aluminum heads in the early 1980s have been eliminated. There are some installation procedures that should be adhered to when installing aluminum cylinder heads for trouble free service.

Chad Golen of Golen Performance, a top notch GM LS engine builder, explained, “Aluminum has more expansion but doesn’t cause a problem with today’s head gaskets and high quality fasteners made by ARP. You just need to be careful bolting up accessories, like intakes and valve covers so you don’t damage the threads.”

Another company that specializes in big block Chevy heads is Livernois Motorsports in Michigan. Mike Schropp, Engine Department Supervisor at Livernois, confirmed that, “While aluminum heads do contract and expand at different rates than the cast iron block they may be bolted to, most modern day gaskets, bolts and heads require little to no maintenance after being installed.”

The key is using good quality gaskets and hardware. “New style gaskets do an excellent job of allowing the two surfaces to scrub on each other and still maintain a seal,” said Schropp. Using the professional guidance from Golen and Schropp, we recommend budget builders to plan on buying good quality gaskets and hardware with an aluminum cylinder head. Schropp also suggested “using an anode rod to try and prevent corrosion of the aluminum surfaces from the dissimilar metals if you are using an aluminum head and a cast iron block.”

Combustion chamber design and volume are important in how the fuel is burnt.

Closed or Open Combustion Chamber?

These terms get thrown around casually without consideration for what they purpose is behind the design of these chambers. In respect to big block Chevy heads, these terms relate to the size of the combustion chamber. An open chamber will have a larger combustion chamber; typically the valves are not shrouded and the engine breathes better. An open chamber can be identified by the dome area of the chamber extending to the diameter of the cylinder bore.

A closed chamber typically has a diameter much smaller than the cylinder bore. The smaller combustion chamber results in the block’s deck surface extending into the combustion chamber area which forces the air/fuel mixture into the smaller combustion chamber when the piston is on the compression stroke.

When the piston nears the cylinder head and the flat area of the piston top and the flat area of the cylinder head get close, the air/fuel mixture is “squished” into the combustion chamber closer to the spark plug. This is where the term “squish area” comes from. The space between the flat area of the piston top and the cylinder head typically run cooler than the rest of the chamber and piston. This lower temperature is where the term “quench area” comes from.

Semi-open combustion chamber heads can flow extremely well and provide the right mix of turbulence and "squish".

While the terms “quench” and “squish” are often used interchangeably by many manufacturers, quench and squish are not the same thing, nor are they produced by the same set of conditions. The Society of Automotive Engineers (SAE) has defined squish as the gases trapped between the piston dome and head that are ejected across the combustion chamber at high speed by the near-collision of the piston dome and head, causing turbulence and mixture homogenization. For our purposes, if the squish area is too close, there is a pumping loss and if the area is too far apart there will be lower squish velocity and less turbulence.

Quench on the other hand, is the ability to lower temperature of the end gases trapped between the piston dome and head by conduction. This prevents a second flame front from igniting the air/fuel mix prematurely. Members of the SAE acknowledge that for motors with 3.5” to 4.5” cylinder bores, a quench distance of 0.035” to 0.040” work well and result in near zero clearance due to thermal expansion, rod stretch and piston rock-over.

Properly designed quench areas have a dramatic effect on combustion quality and allow for higher compression ratios. For our budget friendly cylinder head guide, we can say in general terms, closed chambered heads can have an advantage in fuel efficiency and emissions by achieving a more complete burn, but valve shrouding can become an issue if the chamber is closed too much.

Combustion chamber size plays a significant role in compression (more is less and less is more). The smaller the combustion chamber, measured in cubic centimeters, the higher the compression will be.

Intake Port Shape and Size

It doesn’t take a lot of imagination to understand that a larger port has the potential to flow more than a smaller port. How much flow your engine needs will vary based on how much the engine can use. Port size is a very important issue when it comes to head design. Simply speaking in terms of flow, the smaller the port diameter, the less air potential there is.

Runner volume (length) is also very important. As the runner gets longer, movement in the column of air will increase the flow at lower RPMs and decrease the flow at higher RPMs.

Intake port shape and size are important considerations in reaching your goal.

If you intend on doing a lot of low rpm street driving with a low-lift camshaft, performance will be less than optimal on cylinder heads with huge intake ports. The reverse is also true; high revving, big lift cammed engines with big displacement will not like smaller intake ports.

It’s true that a larger intake runner will allow more air and atomized fuel to flow through, but the larger area will also slow the velocity of the air and fuel flowing through it. Smaller runners speed up the flow, which improves throttle response and torque, but may not deliver the maximum amount of energy that your engine can use. The perfect combination of good flow and velocity is the challenge.

Common thought on port shapes is that oval shaped ports leave fewer opportunities for eddies and irregularities of flow in the corners because there are no corners, however, for budget friendly street heads running on pump gas, you should think of oval and rectangular ports as a function of size, not of shape.

RPMs are a big deal for street cars running on pump gas. Port shape is not as important as the cross sectional diameter and length of the runner matched to the RPMs. It’s highly unlikely that a street car is going to be spinning 7,000 RPM from stoplight to stoplight, thus a huge diameter, big volume oval port runner will probably under perform in the street RPM range.

Runner volume can make or break a daily driver.

Exhaust port shape and runner volume is even less important than the intake side, however, scavenging all the exhaust gasses from the combustion chamber means that you can refill the combustion chamber with more fuel and air. More fuel and air means more power, so there is some consideration in the exhaust runner size and exhaust port shape. Our best advice is to call the manufacturer’s tech lines or talk to your engine builder for guidance on runner size.

Comprehensive Guide to BBC Cylinder Heads by Application

For our guide, we chose to break down the “budget friendly” BBC cylinder heads into categories that include the entry level and work up to the street/strip category and up to the dedicated performance car level. We also include a breakdown on why we think the cylinder heads represented in each category are the best fit for the application. The cylinder heads are not listed in order of preference, simply by the company’s name in alphabetic order. Where applicable, we have included additional information on engine size as big block Chevy’s covered in this article range from engines manufactured from 1965 through 2006.

Budget Big Block Chevy Cylinder Heads For Entry Level Street

Looking for an entry level set of heads for street use goes beyond price. Given that GM factory production heads commonly had runner volumes of 230 to 270 cc. Larger volume runners were used in GM’s performance versions. Aftermarket cylinder heads have improved airflow but must be matched to the camshaft, intake and exhaust systems for the optimal results. The heads listed below are good choices for an application that is intended to be higher performing than stock and still used on the street for daily driving.

Smaller ports and runners will keep the mixture of air/fuel at a higher velocity making driving from stop light to stop light and idle quality a lot more steady. With too large of a runner volume, a basic stock type engine will lug at low RPMs until it gets to cruising speed. Entry level heads are designed for engine where there are not too many high performance upgrades already installed and the engine will be running on mid to high octane pump gas. Optimal runner volume for these conditions is somewhere in the range of 270 cc to 290 cc.

Dart 308cc Big Block Chevy Heads, Rectangular Port

Dart 308 cast iron cylinder head.

Perfect for: Entry Level Street or Street/Strip where front end weight is not an issue.
Material: Cast Iron Alloy
Cost: $1,700 per set
Intake Runner: 308cc
Combustion Chamber: Heart Shaped, 121 cc

• Additional Specs:
  • Part Number: 15100111
  • Intake Port Shape: Rectangular
  • Intake Runner Volume: 308cc
  • Exhaust Runner Volume: 129 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.660″
  • Springs Per Valve: Single
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995),  454 ci Gen VI (1996-2000)

Edelbrock E Street 290 aluminum cylinder head.

Edelbrock E Street 290 (#50459)

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,725 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style, 110 cc

• Additional Specs:
  • Part Number: 50459
  • Intake Port Shape: Oval
  • Intake Runner Volume: 290 cc
  • Exhaust Runner Volume: 110 cc
  • Exhaust Port Shape: D-Port
  • Intake Valve Diameter: 2.190″
  • Intake Valve Angle: 26°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 26°
  • Maximum Valve Lift: 0.700″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1963), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995)

Patriot Performance Freedom Series 2211 aluminum cylinder head.

Patriot Performance Freedom Series (#2211)

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,400 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary, 119 cc

• Additional Specs:
  • Part Number 2211
  • Intake Port Shape: Rectangular
  • Intake Runner Volume: 320 cc
  • Exhaust Runner Volume: 125 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.600″
  • Springs Per Valve: hydraulic roller springs
  • Retainer Locks: 7°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Priced around $1,400 per set
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Summit Racing cast iron cylinder head.

Summit Racing Cast Iron (#SUM-152125)

Perfect for: Entry Level Street or Street/Strip
Material: Cast Iron
Cost: $1,500 per set
Intake Runner: 308cc
Combustion Chamber: Heart shaped 119 cc

• Additional Specs:
  • Part Number: SUM-152125
  • Intake Port Shape: Rectangular
  • Intake Runner Volume: 308cc
  • Exhaust Runner Volume: 129 cc
  • Exhaust Port Shape: Square
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.660″
  • Springs Per Valve: Single
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995)

Trick Flow Specialties PowerOval 280 aluminum cylinder heads.

Trick Flow Specialties PowerOval 280

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,850 per set
Intake Runner: 280 cc
Combustion Chamber: Open Chamber 113 cc

• Additional Specs:
  • Part Number: TFS-41300001 / TFS-41300002
  • Intake Port Shape: Oval
  • Exhaust Runner Volume: 137 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.190″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.700″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

World Products Merlin Oval Port Iron Heads

Perfect for: Entry Level Street or Street/Strip
Material: Cast Iron
Cost: $1,675 per set
Intake Runner: 269 cc
Combustion Chamber: Open Chamber 119 cc

World Products Merlin Oval Port Iron Heads.

• Additional Specs:
  • Part Number: 030040-1 (Hydraulic Flat Tappet)/ 030040-2 (Solid Flat Tappet and Hydraulic Roller)
  • Intake Port Shape: Oval
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.300″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.600″
  • Springs Per Valve: 030040-1: Single. 030040-2: Dual
  • Retainer Locks: 7°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Street Performance & Muscle Car

Typically a bigger valve, port size and runner volume are desired in higher performance applications, however, knowing that this guide is for budget friendly, pump gas, street cruisers, we were looking for runner volumes in the range of 290 cc to 320 cc. On the smaller cubic inch big blocks, it’s probably still wise to stay down in the 290 cc to 305 cc range for drivability.

454 cubic inch big blocks are considered small by today’s standards where 502 ci and 572 ci engines are becoming more common. Obviously, a 454 ci engine will not have the same airflow demands as a 572 ci engine. The cylinder heads listed below still have good drivability in stop-and-go driving situations and low speed response while giving improved performance at the top end.

Dart 345 cast iron cylinder heads

Perfect for: Street Performance
Material: Cast Iron
Cost: $1,800 per set
Intake Runner: 345 cc
Combustion Chamber: Heart Shaped 121 cc

Dart 345 cast iron cylinder head.

• Additional Specs:
  • Part Number: 15200132
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 129 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.300″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.660″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995),  454 ci Gen VI (1996-2000)

Edelbrock Performer 454-O aluminum cylinder head.

Edelbrock Performer 454-O

Perfect for: Street Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style 110 cc

• Additional Specs:
  • Part Number: 60479
  • Intake Port Shape: Oval
  • Exhaust Runner Volume: 110 cc
  • Exhaust Port Shape: Square
  • Intake Valve Diameter: 2.190″
  • Intake Valve Angle: 26°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 26°
  • Maximum Valve Lift: 0.700″
  • Springs Per Valve: Single
  • Retainer Locks: 7°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Patriot Performance Freedom Series 2214 aluminum cylinder heads.

Patriot Performance Freedom Series (#2214)

Perfect for: Street Performance
Material: Aluminum
Cost: $1,600 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc

• Additional Specs:
  • Part Number: 2214
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 125 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.700″
  • Springs Per Valve: dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

RHS Pro Action 320 cc Hydraulic Roller

Perfect for: Street Performance
Material: Cast Iron
Cost: $1,575 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary Modified 119 cc

RHS Pro Action 320 Hydraulic Roller cast iron cylinder head.

• Additional Specs:
  • Part Number: 11301-02
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 135 cc
  • Exhaust Port Shape: Rectangular
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.600″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995),  454 ci Gen VI (1996-2000)

World Products Merlin Rectangular Port Iron Heads.

World Products Merlin Rectangular Port Iron Heads

Perfect for: Street Performance
Material: Cast Iron
Cost: $1,675
Intake Runner: 320 cc
Combustion Chamber: Open Chamber 119 cc

• Additional Specs:
  • Part Number: 030620-2 (Solid Flat Tappet & Hydraulic Roller)/ 030620-3 (Solid Roller)
  • Intake Port Shape: Rectangular
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.300″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 030620-2: 0.650″ / 030620-3: 0.700″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Wild Street and Dedicated Performance

For an application where performance is desired over streetability comfort. The heads listed below are for larger cubic inch big blocks where the airflow demands are greater or highway driving where the engine does not have to lumber through the gears to get to cruising speed often. Once you get to cruising speed however, these heads should provide all the flow you need or want.

Cylinder heads in the dedicated performance category will do well with intake and exhaust upgrades that maximize the flow characteristics. Large port openings and runner volumes along with larger valves and valve train set up for higher lift are the standards of a wild street or dedicated performance head.

Edelbrock High Compression 454-O aluminum cylinder head.

Edelbrock High Compression 454-O (#60499)  50 state legal

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style 100 cc

• Additional Specs:
  • Part Number: 60499
  • Intake Port Shape: Oval
  • Exhaust Runner Volume: 110 cc
  • Exhaust Port Shape: Square
  • Intake Valve Diameter: 2.190″
  • Intake Valve Angle: 26°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 26°
  • Maximum Valve Lift: 0.700″
  • Springs Per Valve: Single
  • Retainer Locks: 7°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Trick Flow Specialties PowerPort 320 aluminum cylinder heads.

Trick Flow Specialties PowerPort 320

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,950 per set
Intake Runner: 320 cc
Combustion Chamber: Open Chamber 122 cc

• Additional Specs:
  • Part Number: TFS-41400001 or TFS-41400002
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 137 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.700″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Patriot Performance Freedom Series (#2216)

Patriot Performance Freedom Series 2216 aluminum cylinder heads.

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc

• Additional Specs:
  • Part Number: 2216
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 125 cc
  • Exhaust Port Shape: Round
  • Intake Valve Diameter: 2.300″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.800″
  • Springs Per Valve: Triple
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

RHS Pro Action 320 cc Solid Roller

RHS Pro Action 320 cc Solid Roller cast iron cylinder head.

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,780 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc

• Additional Specs:
  • Part Number: 11301-03
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 135 cc
  • Exhaust Port Shape: Rectangular
  • Intake Valve Diameter: 2.250″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.750″
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995),  454 ci Gen VI (1996-2000)

RHS Pro Action 360 cc Solid Roller cast iron cylinder head.

RHS Pro Action 360 cc

Perfect for: Wild Street Performance or Dedicated Performance
Material: Cast Iron
Cost: $1,780 per set
Intake Runner: 360 cc
Combustion Chamber: Proprietary 119 cc

• Additional Specs:
  • Part Number: 11302-02 (Hydraulic Roller)or 11302-03 (Solid Roller)
  • Intake Port Shape: Rectangular
  • Exhaust Runner Volume: 135 cc
  • Exhaust Port Shape: Rectangular
  • Intake Valve Diameter: 2.300″
  • Intake Valve Angle: 24°
  • Exhaust Valve Diameter: 1.880″
  • Exhaust Valve Angle: 15°
  • Maximum Valve Lift: 0.600″ (11302-02) / 0.750″ (11302-03)
  • Springs Per Valve: Dual
  • Retainer Locks: 10°
  • Valve Train: Standard BBC  7/16” Stud Mount
  • Guideplates: Hardened Steel, 3/8″ Pushrod size
  • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995),  454 ci Gen VI (1996-2000)

The Final Word

It’s been said that the terms “budget” and “big block” don’t go together and qualify as an oxymoron when used together. However, the cylinder heads listed in our guide above are well within the range of what can be considered budget friendly. Nan Gelhard of Summit Racing Equipment emphasized that point by saying; “When you talk about dollars per horsepower you can see how it changes as you go from street to strip.”

Whether you have a stock big block that you salvaged from the wrecking yard and are looking for some modern technology heads to bolt on, or if you want to beef up your daily driver to take it to the drag strip occasionally, we’ve got you covered in one of the budget friendly categories listed above.

Billy Mitchell Jr. from World Products encourages enthusiasts to call the tech lines or work with your engine builder. “It’s important to marry the runner size and port shape to the cubic inch size of the engine,” says Mitchell. Chad Bowling of Patriot Performance also recommended working with your engine builder on the engine internals like camshaft before picking a set of assembled heads, “Most aftermarket head manufacturers offer cylinder heads in a variety of spring packages from hydraulic flat tappet to solid roller,” Bowling states. The final word is that it is OK to use this guide as you would any other guide, as a means of gathering information to talk with your engine builder about the best method of achieving your goals.

A lot of people are always asking themselves what the meaning of life is. To us, life is all about evolving. Evolution is everywhere you look. It happens every day in fashion, movies, and music. Well maybe except for music. But even the way we listen to music today compared to how we did 10 years ago has evolved; look no further than MP3’s and iPods. When we growing growing up, you were cool if you had a portable CD player, especially one that didn’t skip constantly.

The engine that started the legacy, the 265, was Chevrolet's first foray into affordable V8 performance in an entry-level sedan, not that of a big full-sized performer.

So evidently, evolution is a good thing, and the small block Chevy engines that have been pumped out of the General’s engine plants all over the world are no exception.

With the small block making its debut for the 1955 model year, no engineer back then could have imagined where we would be today with 638hp, 376 cubic inchers that are still able to pull 26mpg on the highway and produce low 11-second quarter-mile time slips off of the showroom floor!

But like everything else; there were setbacks, growing pains, and something called the Smog Era, which was basically like the dark ages for automotive technology. As usual, GM weathered the storm and got us through it, and what resulted is the modern LS family of today.

Today, the small block Chevrolet is one of the most iconic mainstays of the hot rodding industry. From boats, small aircraft, to lakesters and European knock-offs, the SBC is a legend not due to its numbers but its longevity.

265

In a thread that would follow the small block throughout its existence, the original 265 can trace its existence back to the never-content engineers and speed freaks in the Corvette division. Looking for a suitable replacement of the “stove bolt” inline-six, Ed Cole and Zora Arkus-Duntov birthed the plant in a furious 15 weeks.

The 265 small block was released in the all-new for ’55 Chevrolet models ranging between either a 162 or 180hp carburetion and camshaft package. A huge step in placing Chevrolet in the public eye as an “everyman performer,” this engine carried over for ’56. It was an available option for all Chevrolet passenger cars, pickups, and was instrumental in raising the prestige of the Corvette.

283/327 heads were essentially the same castings. Photo: Ray's Chevy Restoration

283

With a release in the final year of the “Tri-Five” – the 1957 Chevrolet – and being the first Chevrolet engine offering factory fuel injection at the lauded 1hp-per-cubic inch output, the 283 was one impressive engine for its time and it’s considered a milestone in Chevrolet history. Originally, the 283 was merely an overbored 265, but engineers found that the previously-cast block’s walls were thin. A thicker-cast block needed to be produced.

Five variations of the 283 were made available in 1957 alone, ranging from 185hp to 283hp thanks to the option of a single, dual carburetor or “Fuelie”induction system. The Rochester-built mechanical fuel injection rose as the crème de le crème of the 283 packages. The fuel injected version of the 283 was also an available option on the passenger car line as well as the Corvette, making anything powered by this rare and unique plant a collector’s item today.

327

Introduced in ’62 and available on all models from the compact Chevy II to the sporty Corvette, the high-revving 327 came in a variety of specifications throughout its short-lived lifespan ranging in horsepower numbers of 210 to 375, respectively.

The highlights being the 365hp L-76, and the 375hp L-84 which the latter included mechanical fuel injection, and was the highest horsepower-per-cubic-inch engine (1.146hp-per-cube) ever offered by the manufacturer until the Gen III LS6 of 2001 came along. The 327 essentially used the 283 cast iron heads, but with larger valves.

302 (DZ)

Only being available for three model years, and offered exclusively as the standard engine in the Z/28 Camaro of ’67-’69, this “little engine that could” combined components from the 283 and the 327, respectively, having been designed primarily for the Camaro’s entry into the Trans-Am racing series.

The reason for such a small displacement was the rules set by the T/A series and the SCCA (Sports Car Club of America) that no vehicle was to displace any engine larger than 305 cubic inches. The end result of this combination of parts would result in a factory-proclaimed, but underrated 290hp, although some say the real output was closer to 350hp.

These engines would go on to be synonymous with the first generation Z/28, and though it wasn’t much of a 1/4-mile star with times in the low-15s, that high-revving 302 would scream around any road course you put it on.

We talked to Ron Sperry, GM’s Powertrain Component Design Engineer who was hired on at GM in 1969, about the famous 302, “These were developed before my time, and most of the guys who had engineered them had their work cut out, since it was an all-new idea at the time. Depending on application, the only real difference between any of these castings were the valvetrain pieces, and the casting numbers, but they were excellent units for their time given the technology they had to work with in those days.”

350 SBC Head. Photo: Chevy High Performance

350 (L-46, L-48, L-82, LT-1)

The 350 was the longest-lived small-block Chevrolet engine made, and it has powered everything imaginable. In it’s initial form, it was introduced as the 300hp L-48 in the ’67 Camaro, and eventually found its way into all of the other Chevy models as time went on. The high point of this powerhouse was the 360hp variant that was the LT-1 version. As performance (or what was left of it) limped along during its absolute low-point during the mid-‘70s to the early ‘80s, the Corvette made due with an underpowered, though somewhat respectable for the era, L-82, producing in the neighborhood of 200hp, depending on year.

Although the engine was finally put to rest in most applications around the turn of the century, they were still being produced in Mexico until 2004, as a result, over 90,000,000 Gen 1 small block Chevys were made. The latest and highest performing (in net numbers) version dubbed the L98, which we’ve decided to give it’s own section as it was the only MPFI Gen-1 350 that was made.

Ron explained, “I was hired on at GM in 1969. By that time, the L-48 was already up at running under the hoods of many Chevy muscle cars. What many people don’t realize is that these heads would change very little until the mid-’70s, when fuel economy and emissions took over as the key factor over performance, we would later go on to develop the ‘swirl port design’ that would live on in models until the late ’80s.”

Aluminum L98 heads shown. Photo: eBay Motors

Proving that Chevrolet was making an effort in injecting its models with much needed performance during the ‘80s was the aluminum head version of the L98.

While often over-looked by builders today, the factory castings of these heads have been reincarnated as the GMPP ZZ4 head, and they are still available over the counter at any GMPP retailer.

“These were the first purpose-built, factory-produced high performance heads in a long time,” Ron clarified. “The aluminum L98 castings were the result of our racing efforts, and it showed as it gave the Corvette and F-cars the much needed performance they rightfully deserved.”

400

As a way of attempting to maintain horsepower levels while slashing compression ratios, the 400-cubic-inch small blocks arrived just in time to see the pinnacle of classic high-performance in ’70 with 265 gross horsepower, before having its plug pulled after the ’76 model year with it producing 175 net horsepower. It was found in everything from intermediate-sized coupes, to full-sized pickups.

Although it never was truly a performance engine (with smog-era 350′s of the same vintage producing more power), it would later become a favorite among circle-track and drag racers for a time, most likely due to their plentiful and bargain-priced availability.

Even so, these heads – also known as the 882 castings – had a double heat-riser passage and were prone to cracking because they ran so hot. With the current aftermarket now producing better offerings, personally, we would leave these on the shelf when it comes time for your next engine build.

Ron Sperry (fourth from left) pictured with the rest of GM Racing's R07 NASCAR engine team.

LT5

In an effort to dig a little deeper into the history of these classic heads, we enlisted Ron’s help. Sperry was involved with developing a number of the different SBC engine pieces found in a large variety of GM’s performance offerings, most notably, the aluminum TPI, LT5, LT1/4, and the original LS1 heads.

LT5 casting. Photo: ZR1.net

Kicking off the ‘90s with a bang was the aluminum head LT5 that was exclusively found in the original ’90-’95 ZR-1 Corvette. It was produced in partnership with Lotus and Mercury Marine, and was purely designed with performance in mind. No other variants were made of this engine, and it’s the lone DOHC unit on our list.

Although the LT5 maintained a DOHC, 4-valves-per-cylinder design throughout its life span, changes were made during the run, and as a result, horsepower levels changed, as did the casting numbers. Spark plugs were located in the center of the combustion chamber for maximum power.

There were there different versions of the LT5 cylinder head, although they are all very similar. This cylinder head is unique to the LT5 Corvette engine, and is not compatible with any other engine platform.

LT1/LT4

Following hot on the tail of the LT5, and designed as a replacement for the L98 head, came the short-lived LT1. Not to be confused with the LT-1 of 1970, the Generation II small block’s head came in either aluminum or iron, and packed anywhere from 260hp-315hp (depending on application).

While the aluminum versions were found exclusively under the hoods of F-bodies and Corvettes, it was in the full-sized B-body car line (Caprice, Impala SS, Fleetwood, Roadmaster) where the iron head version resided.

But before the LT1 was killed off, a limited run of LT4 engines were created to send the Generation II small block out with a bang with a total of 330hp. While the castings were similar and the bolt patterns identical to the standard LT1 (making it very possible and very popular for a head swap for tuners), it was in the port design that made all of the difference.

“These were the first real redesign of the SBC head as we knew it,” Ron remembered. “Where the L98 Corvette was making at best, 250hp, these heads in combination of the changes we made with the LT1 engine itself were good for another 50hp, up to a total of 300 for the ’92 Corvette. After this point, the Corvette design team had to refocus their efforts on the chassis of the car, as the increased horsepower and torque changed the driving dynamics of the earlier C4 design.”

LS9 head pictured. Photo: GMPP

It All Comes to A Head

The LS series of engines picked up where the LT1 and LT4 left off with the introduction of the C5 Corvette. It would later go on to revolutionize the SBC as we know it, earning the moniker of “Generation III,” although many LS loyalists within the hobby struggle to acknowledge them as small block Chevy plants.

Having said that, unless you’re into date-code numbers correct, concours originality, we see no point in scrounging for rusty, used relics from a swap meet for your high performance needs, when the aftermarket currently offers limitless amounts of options for your small block Chevy. With where we are in terms of technology and design, you would only be going backwards anyway, and where’s the fun in that?

We would like to personally thank Ron Sperry for his time and courtesy to take a few minutes to talk to us about the evolution of the Gen 1 and Gen 2 heads, and we look forward to working with him again in the future for other feature articles.

Most of us count our horsepower by the hundreds. However if you’re a racer or engine builder who counts in the thousands, you’re not building with parts you bought out of a catalog. Engine builders and racers at this level are in the upper echelon of the racing world. There’s only a handful of guys currently building horsepower at this level and many of those builders turn to Dart.

A finished Dart Machinery billet aluminum block is as much a piece of modern art as it is a hardcore racing part. CNC machines carve each block from a single 6061 billet block in a process that can take upwards of 40 hours.

Custom Built To Your Specifications

“The engine builders who work at this level tend to have very specific ideas about what they want. Everyone has their own specifications and Dart produces components to meet their needs,” explains McInnis.

Common design variations:

• Custom deck heights up to 12.500-inches
• Variations in deck thickness
• Variations in bore size from 4.840-5.300-inches, spacing, angle and location
• Raised camshaft location up to 1.915-inches
• May or may not include water jackets in the block
• Wider pan rails.

All of these options play into an engine builder and racer’s master plans for producing an optimized engine combination. Builders must be on their toes and prepared to account for a wide range of variances based on their design demands. When dealing with parts at this level, you have to assume that nothing is going to be normal.

According McInnis, “Using this approach, most custom block designs are completed in 2-4 weeks. A total new design of an engine platform we have not previously worked with would of course take longer.” This is because Dart has predetermined, pre-engineered CAD files already in their computer system. Those files serve as a design template and are altered to meet each individual engine builder’s design demands. This can also streamline the design process because engineers have information readily available as to what’s already feasible in the real world.

Offset and custom sized lifter bores are just one customizable feature available on a Dart billet block.

Dare To Be Different

McInnis explained to us,”You’re really only limited by the internal parts that you can source. You could theoretically do almost anything. Whether you can find the parts to use is another part of the story.” Dart engineers work one on one with engine builders to develop their design ideas, test them for real world feasibility and make them a reality.

Simple variations like adjusting tall deck heights or thicker pan rails, thickness, or unique head bolt patterns, to more radical alterations such as extreme bore spaces or combining engine platforms, the engineers at Dart are up to the task of helping the racer and engine builder achieve those goals. With a Dart billet block system, if you wanted to run a Ford Modular cylinder head on a Chevy big block or vice versa, the engineers at Dart can work with you to make that happen.

Making Big Cubic Inches

In small block applications builders can choose from 4.400″ or 4.500″ bore spacing, while big blocks have the option of running 4.840″,  5.000″, 5.200″ or a whopping 5.300″ bore spacing, which have become the staple in Pro Modified, mountain motor racing.  Deck height for big blocks can also hit a ceiling of up to 12.50″ to help produce over 1,000 cubic inches.

Cylinder heads and valvetrain geometry often start to become a challenge at this level and you may need to communicate with a valvetrain engineer and a cylinder head expert. Dart can help compensate for these large bore sizes by offsetting the lifter bores. Lifters and other components must be able to handle the design parameters of such an engine operate properly. You could in theory design nearly anything in the CAD process, but the difference between theoretical and reality have to come into play at some point.

Camming Up

Changes in cam height in the blank are common when building engines on this level. Builders may want to move the cam in the block, and block builders can run a cam tunnel diameter of up to 70mm (60mm max size in small blocks). Dart billet big blocks can raise the cam by as much as 1.915″.

• Allow clearance for longer crankshaft strokes
• Allow for larger camshaft bores in the block
• Shortens the length of the pushrods to reduce or help control valvetrain

From CAD To The Real World

You Dream it, They Make it Reality

The combination of CAD and CNC technology allow for nearly anything an engine builder can dream up. Variations in pan rail design, bore size and spacing, water jackets, cam height, lifter bore size and offset are just some of the many design features that can be incorporated into each block.

 

Once all the details have been established and everything is worked out by the engineers in CAD it’s on to the next step. It is critical during the design phase that engine builders work very closely with Dart’s design engineers. Further, every component to be used by the builder must already be determined. These components must also be known as compatible for the application; at this level of design those small details make the difference between having a working racing engine and an expensive piece of decorative aluminum.

What is 6061 Billet Aluminum

Each billet big block starts life as a 500-pound block of 6061 aluminum. All of the billet material that Dart uses come from a drawn process where the aluminum is drawn over rollers while it’s still hot after pouring. This helps compress and align the aluminum’s grain structure to ensure quality, strength and durability. This process alone takes over 18 hours to ensure the proper heat treatment and strength. To withstand the demands of the highest horsepower engines the materials used must be superior.

Facts about 6061 aluminum:

• Material must be 95.8% or more aluminum by weight.
• Tensile strength of 45,000 psi
• Shear strength of 30,000 psi
• Rockwell A Hardness 40
• Rockwell B Hardness 60
• Fatigue strength 14,000 psi
• Melting point 1080-1205° F

Creating a block

Cutting a block from a single billet piece of rather than a traditional casting is a proven way to improve strength and durability. When casting a large part such as a block there can be core shifts and other errors in the process that can cost the manufacturer time and money. This can also compromise the structure of the block and could potentially be unnoticed during the manufacturing process. Carving the block on a CNC machine from design parameters created in CAD eliminates this type of potential error.

The foundry inspects each billet on a microscopic level to identify where the core is strongest. This designated area of the core is where Dart will machine the main crankshaft journals, ensuring this critical area of the block is in the strongest portion of the material.

Once received from the foundry, the blocks are rough cut or cut into a blank. At this point the block will truly begin to look like an engine block with the basic shape and form. Blocks are then given a proprietary heat treatment that further strengthens the billet. By doing this to a block when it’s still at the blank stage, it ensures that critical areas are not distorted during the final heat treatment process.

Finishing Up The Foundation

Engine builders can specify aluminum or steel main caps as options on Dart billet blocks.

Following heat treatment, Dart’s billet blocks spend several more hours in the CNC machine receiving final machining to create a piece that’s exact to the design specifications. Completed blocks are thoroughly inspected for quality control, using tools such as CMM’s (coordinate measuring machine) to ensure optimum build quality and proper specifications.

Once this work is complete, the block can either be shipped to the engine builder so that they can perform their own final machining or reamins at Dart performs these steps in-house, including line honing and the installation of ductile iron cylinder sleeves. Once all is said and done, the original 500-pound billet has been transformed into a 150-pound big block Chevrolet engine block.

From the time Dart gets the go ahead and final approval on the CAD design, it takes 10-12 weeks to complete a custom block. This isn’t very long considering the amount of customization that’s available and the overall quality of the part.

Billet Cylinder Heads

Engine builds at this level will require custom built or billet heads as well. Dart’s billet offering can either be of Dart’s own design the engine builder’s. Because Dart controls the entire block design process, the head design and manufacturing process can be done in a similar fashion.

Dart Cast or Billet Aluminum heads can be run with Dart Billet blocks. These heads are not your typical off-the-shelf mail order pieces. All heads for billet engines are custom tailored to fit the design specifications of the builder and the block being used. Here you can see a set of custom heads for an engine with 5.20-inch bore spacing.

Says McInnis, “Depending on the type of racing and engine platform, some customers are running cast aluminum heads and some are using billet heads.” Either way, these are not direct off the shelf parts. While a raw casting may be waiting for machining at Dart’s facility it’s not a ready to ship part.

Dart heads may feature valve sizes of 2.575″ on the intake side or conceivably larger in some applications. They in many cases also utilize titanium valves and copper beryllium seats. Cylinder head parameters are influenced greatly with changes in block and head design. For example when utilizing the 5″ bore spacing builders can be dealing with camshafts of 1″ or more of gross lift. Spreading the cylinder bores out this much also allows for massive runners in the cylinder heads. Heads in this case can flow in excess of 560 cfm.

More than Just Drag Racing

A Dart customer recently ran 3.74 in NHRA Top Fuel qualifying. While obviously the kind of power levels that we’re talking about required to even effectively use a billet block include, Pro Mod’s, Top Fuel and Funny cars, Dart billet products are not limited to just Drag Racing.

Billet blocks are used in dirt track, off road racing, marine, and even some street car applications. Due to the level of customization and strength, the billet blocks go well beyond the power levels a regular cast block can support. Dart also allows for engine builders to use their imagination to possibly create a whole new type of engine designed for one aspect…breaking records.

To recap the on-going engine buildup for our Project BlownZ being built for the NMCA/NMRA West 275 Drag Radial Class, the first two parts covered the short block assembly in detail (block prep and short block assembly) on this 388ci, ProCharger F1-blown LS motor. This time around, we’ll go into detail on the Trick Flow Specialties/Total Engine Airflow cylinder heads, what they’re all about, why they were chosen for this application, and what kind of work was done to them.

The cylinder heads are one of the most crucial parts of the engine when it comes to making power—peak power, what the power curve looks like, and how much torque it makes and where. The Limited Street rules we originally built this engine for limit cylinder heads for a boosted GM LS engine to be within one degree of the stock 15-degree valve angle without a weight penalty. We are also limited to using no bigger than an F-1R ProCharger supercharger at our weight break.

We put a lot of thought into the cylinder head choice for the ProCharged 388ci LSX for Project BlownZ, and in the end we went with a set of Trick Flow's LSX-R 265 heads and let the guys at Total Engine Airflow work their magic on them.

Trick Flow LSX-R 265 Cylinder Heads

Taking both of those rules into mind, Shawn Miller of Virginia Speed, called the guys at Trick Flow Specialties for some advice. After much discussion they decided that the best thing was to provide a set of their TFS 265cc LSX-R heads and let Total Engine Airflow in Tallmadge, Ohio port the head for maximum flow. When TEA and Miller got together, they decided bigger is better on the ports and created what Miller calls the 265 head.

Total Engine Airflow CNC-ported the intake and exhaust runners to huge volumes, and shaped the combustion chambers as well. The flow at .700 lift is an astonishing 368 and 298 cfm.

Trick Flow’s Cory Roth said, “We offer this head as a casting for cylinder head shops to buy and put their magic into. We call it an ‘X casting’ for extra material.” The official name is actually the Trick Flow LSX-R Cylinder Head, part number TFS-306003-PC05. Trick Flow’s Mike Downs said, “This is the starting point for the Total Engine Airflow TEA-LS265TF cylinder head for 1997 and later large-bore GM LS engines—the 265cc drag head. It’s our largest offering in a cathedral-port design yet.” He added, “You’ll have to turn the engine a lot of rpm to make up for the small blower, so the 265 head is a good match to really let it breathe.”

After installing copper beryllium seats, they were cut on this Serdi machine to a drag race-only 55-degree seat angle.

Trick Flow’s LSX-R casting has raised spring pockets, rocker pads, and valve cover rails to allow for high-lift cams and valve train components. It is only available in a 6-bolt version. This head is designed for drag race only and uses a competition only 55-degree valve job and titanium intake valves. This creates great airflow benefits at high valve lifts of .700-inch and up. The bare casting has room for obscenely large ports and has a valve angle of 13.5 degrees as delivered, and 64cc chambers.

A look at the profiled chamber, cut to 59 cc of volume.

TFS-306003-PC05 Trick Flow LSX-R Cylinder Head Standard Features

• Material: A356-T6 Aluminum
• Combustion Chamber Volume: 64cc CNC-profiled Standard
• Intake Port Volume: 265cc CNC Ported
• Intake Port Location: OEM
• Intake Valve Diameter: 2.10
• Intake Valve Material: Titanium
• Intake Valve Seat: Interlocking Ductile iron
• Exhaust Port Volume: 85cc CNC Ported
• Exhaust Port Location: OEM
• Exhaust Port Dimensions: 1.700″ x 1.550″
• Exhaust Gaskets: Stock Gm
• Exhaust Valve Diameter: 1.600″
• Exhaust Valve Material: Stainless Steel
• Exhaust Valve Seat: Ductile iron
• Valve Guide Material: Bronze alloy
• Valve Seals: Viton fluoroelastomer
• Minimum Bore Diameter: 4.155″
• Cylinder Head Bolts: OE Length
• Spark Plugs: NGK-TR6
• Valve Covers: OE bolt pattern, raised 0.200″

Miller said, “The 265 is TEA’s race casting. It’s a lot beefier and stronger than the older TFS LS head, which was more of a street head. This one is geared more towards racing. It has six bolts [per cylinder] for LSX and RHS blocks, big 1.650-inch spring pockets, room for bigger pushrods, and just more meat everywhere. Also, it is one of the best cathedral-port heads in existence in regards to flow.” Yes, this is still a cathedral-port head. On the exhaust side they went with what TEA calls the “nitrous port” which features more aggressive porting to flow more air than a standard runner.

It’s true, a cathedral port head can flow huge air. This one does, to the tune of 368-plus cfm at our max valve lift. This is TEA’s optional “nitrous” exhaust port that we opted for. It flows 298 cfm at .700 lift, compared to the standard exhaust port’s 272 cfm.

Total Engine Airflow Head Work

To comply with the original Limited Street valve angle rule, TEA reverse angle-milled the head from its as-delivered 13.5 degrees to 14 degrees. As Downs explained, “That’s opposite from why you normally angle-mill a head, where you decrease the valve angle. We increased it.” When they were done, the chambers came it at 59cc, which when combined with the pistons we were running, brings the compression to 11.3:1.

The TFS LSX-R heads were designed to be used with a GM Performance Parts LSX block, hence they use an extra set of bolts to lock them down and prevent head gasket problems under extreme cylinder pressure.

FLOW DATA (4.155″ BORE)
Lift —- Intake —- Exhaust —- NO2 Exh.
0.100       59            58               55
0.200      128          129              122
0.300      210          189              199
0.400      281          233              250
0.500      340          256              277
0.600      352          267              290
0.700      368          272              298
0.800      377          274              303
0.900      382          277              305
1.000      388          279              306

* Tests conducted at 28″ of water, 4.155″ bore, 2.0″ Exh. pipe

 

The cam we’re running has a max lift of .777-inch on the intake, .781 on the exhaust, and after hours of porting the ports flow 368/298 cfm of air at .700-inch lift. At .800 lift, close to our max number, the heads are pumping 377 and 303 cfm through the runners. That’s stout for a 388-inch engine.

Ferrea Titanium Valves

Once ported and flow-tested, the TFS heads received copper beryllium seats and Ferrea supplied titanium valves for the intake and stainless valves for the exhaust, all from their 6000 series of Competition valves. As for the titanium intake valves, Ferrea offers some of the finest titanium valves on the market. Their extensive R&D facility is constantly implementing new designs and processes, which continues to stay in the forefront of engine valve technology.

They manufacture each valve by forging a piece of special high-temperature titanium alloy with silicon. The valves then undergo an extensive heat treatment and stress-relieving process to ensure molecular integrity and prolong the valve’s life. “Once we finish the heat treating process we coat the entire valve with CrN coating,” says Zeke Urrutia of Ferrea. “This allows the valve to be used with any type of seat material and guide material.”

The actual valves used in this engine are part number F6302 on the intakes, which is a 2.100-inch valve head with an 11/32 stem and .250 tip size, and 4.910 inches long. Exhausts are part number F6305, with 1.600-inch head, 11/32 stem, and also 4.910 inches long. The intakes have a 10-degree backcut, and the exhausts are 12-degrees.

Each Ferrea titanium valve is meticulously machined in their own precision CNC machining center where it must pass extensive quality control procedures.

Shawn Miller from Virginia Speed installs the Ferrea Valves in the Trick Flow LSX-R 265 heads.

As far as the stainless exhaust valves go, Ferrea’s “super alloy valves” represent what they claim to be the highest level of sophistication in valve technology. Ferrea introduced the next generation of extreme heat resistant valves, specifically developed to withstand the brutal punishment of NHRA Top Fuel and Funny Car applications. They have developed a specially processed high nickel-based alloy, and a unique heat-treatment process, which yields extreme heat resistance and enormous tensile strength properties (far beyond conventional Inconel materials).

"We only use US-military spec titanium for our intake valves," says Zeke Urrutia from Ferrea.

Comp Elite Drag Racing Dual Valve Springs

Controlling the valves at 9,000 rpm, big lift, and high cylinder pressure is not the job of wimpy springs, so Virginia Speed went to Comp Cams for their Elite drag race dual 1.500-inch diameter valve springs, and set them up with 350 pounds of pressure on the seats, and a stout 950 pounds when open. Miller really wanted to use Comp’s lightweight titanium retainers, but at the time the engine was built, Comp didn’t offer them for these springs. Manley titanium retainers were chosen.

When asked about that spring pressure, Miller said, “Forced induction likes a lot of seat pressure. It’ll float the valves really fierce at higher rpm and higher boost. We’ve had fewer problems with excess [pressure] than not enough.”

High rpm and lots of boost means you’ve gotta run a lot of spring, and we handled that with Comp Cams’ Elite Drag Race dual springs with 350 pounds on the seat and a whopping 950 open.

Jesel Rocker Arm Setup

The rest of the valvetrain consists of Jesel’s trick shaft rocker setup for the LS heads, as well as their keyed lifters riding on a custom Comp camshaft and pushing ½-inch diameter pushrods, while a Jesel belt drive connects cam to crank. The valvetrain parts we used with these heads were explained in detail in a previous installment of our 388 LSX’s build saga. 

We finished off BlownZ's TFS LSX-R 265 heads with Jesel's trick long-slot rocker arms.

At this point, you may be asking how much coin you have to shell out for these heads. Well, with any race engine, how much you spend is often directly proportional to how fast you go. In this case, the price tag isn’t offensive. The TFS/TEA heads retail for $3,950, which is really chump change for the amount of power they are set to deliver.

Putting It All Together

Clamping the heads to the LSX block are ARP studs and sealing the block-to-head interface are SCE copper gaskets. Why copper? Miller said, “LS engines inherently have head gasket issues, because of the way the bolt pattern is. There are 10 bolts from the factory, and even with the LSX block with the extra head bolts, they’re a good distance away from the bore. They don’t have the same clamping effect as on a small-block or big-block Chevy. There’s a lot of guys running MLS [multi-layer steel] gaskets on the LS and still having head gasket issues.”

For max strength, ARP studs were used throughout.

In addition to the copper head gaskets, Virginia Speed installed double O-rings, one in the block and one in the head, to seal combustion pressure. Silicone was used around the water ports, and otherwise the gaskets were installed dry, with no other sealant. “We’ve made over 2,500 horsepower on an LS with these gaskets and had no issues,” said Miller. Street guys listen up: you don’t want to run copper gaskets on a street car, as the constant heat cycles in a street application will eventually create a water leak from the gasket.

The head gaskets are no-compromise SCE copper gaskets, designed for a tight seal under extreme cylinder pressure.

What’s Next For the 388 LSX Bullet?

Over the last few months we’ve bolted the whole combo together with our our F1-R ProCharger, dropped it in Project BlownZ, and made some very respectable low 8-second passes. In the next installment we’ll outline how we tuned the 388 LSX on both the track and the dyno. How much power did it make? You’ll just have to wait and see.

The Big Victor is one of more than 40 cylinder heads that can be ordered with the HIP process.

Tech5 is a new feature where EngineLabs asks five tech questions to an industry leader. This week we go behind the scenes at the Edelbrock foundry where select products undergo a HIP treatment. Our guest is Rick Roberts, director of engineering at Edelbrock.

EngineLabs: Briefly describe HIP and how Edelbrock came to utilize the process.

Roberts: HIP stands for Hot Isostatic Pressing, and it originated in the aerospace industry as a way of increasing strength and eliminating defects in metal castings. HIP will take a good casting and make it great by eliminating trapped gases and internal porosity in the casting. Every casting has trapped gases, or internal porosity; it’s the amount of trapped gas or porosity that determines the castings quality and structural integrity. Basically, the HIP process takes raw castings up to 970° F in a pressurized chamber with inert gas (up to 30,000 psi) and compresses the casting to reduce and eliminate any trapped gases. The result is an incredibly strong and dense sand casting that has three times the fatigue life and nearly the consistency of billet aluminum.

The HIP process removes trapped gasses from the casting and improves structural integrity.

We are continually in communication with engine builders and race teams in the industry. We noticed a need for a stronger casting for the cylinder head porter market. In our observation, cylinder head porters were machining a large amount of material out of castings to increase flow and performance for high end racing applications. This was resulting in thin walls and less structure in the casting, which could result in reduced fatigue strength in the casting over time. Plus, cylinder heads receive a large amount of cyclic duty loads in an engine and are vulnerable to fatigue, especially in high velocity applications, such as supercharged, turbocharged and nitrous applications. By offering a HIP processed cylinder head, porters could machine a head with thinner walls for optimal flow without sacrificing casting structure and integrity. The HIP process also extends the fatigue life in the casting, allowing for it to be more consistent over its duty cycle.

EngineLabs: If HIP applies pressure uniformly in all directions while under heat, then the part is actually “squeezed” and its size is reduced. How do you maintain critical measurements?

Roberts: The size is reduced after the HIP process, but not enough to make a difference in the end. It is a minimal amount, so our CAD design is the same for both HIP processed and our standard cylinder heads. Our foundry uses the same tooling and casting process as our non-HIP processed cylinder heads. When machining these parts, we have to reduce the feed rate and increase the rpm to compensate for the denser casting.

EngineLabs: Which Edelbrock parts undergo the HIP process, and what’s the criteria for selecting those part numbers?

From inside the Edelbrock foundry.

Roberts: We only HIP cylinder heads that we believe have the potential of being used in severe duty cycle applications. Some of our cylinder heads applications that are borderline, are offered in both standard castings as well a HIP processed castings for the engine builder to choose from. We offer over 40 cylinder head applications with the HIP process. We have HIP processed cylinder heads available for small-block Chevy, LS series Chevy, big-block Chevy and small- block Ford.

EngineLabs: What are the real and practical benefits to the engine builder in using a HIP part?

Roberts: For the engine builder and racer, HIP processed cylinder heads provide less chance of failure due to fatigue. They also provide a better; smoother machined surface finish when CNC port and chamber work is applied.

EngineLabs: Are there any downsides to HIP parts?

Roberts: This process increases the cost from $100-$400 per cylinder head. It really depends on the amount of aluminum in a casting that determines the final cost difference. There are no weight differences, however.

Some adjustments are made on the CNC machine to finish HIP parts.

TECH5 is a regular feature where EngineLabs asks industry leaders five technical questions. This week’s guest Curtis Boggs of Race Flow Development. Boggs has been instrumental in developing cylinder heads for a wide range of racing applications, include circle track, road racing, Pro Stock and motorcycles.

EngineLabs: Comparing respective intake-port volumes seems like a logical strategy for matching cylinder heads to their proper applications. Is there a catch?

Boggs: It seems simple enough; too big, the airspeed slows, and you have a lazy engine. Too small, you hurt power and the engine won’t rpm properly. For most applications, that’s true. But moving into more specialized engine combinations or high-horsepower-per-cubic-inch, induction systems are more sensitive and this doesn’t work.

EngineLabs: So, what’s the key?

Curtis Boggs

Boggs: Lets discuss cylinder design on its own for a moment. There are several ways to design intake ports, and they all have their use or application. A port that is very large at the opening and tapers down to the valve has an application. But so do ports with the opposite design. And, of course, there are hundreds of variations in between. Some port designers like very large valve bowls. Those aren’t appropriate for everything but do have applications. These variations have a drastic effect on the engine’s “personality.” How the engine responds is application specific. You wouldn’t use a 500ci Pro Stock engine in a LeMans road-race car. Very few port designers have the experience necessary to have full command of this phase of induction design. Simple port volume based on cc’s tells you nothing about the head’s application or port “style.” The two tapered-port examples above are at opposite ends of the design spectrum, yet they both could have the same poured cc volume.

EngineLabs: Okay, applications are specific in high-end racing. But you haven’t told us how to select a cylinder head for a specific application. Why have you confused the subject?

Boggs: It’s really not so difficult. On engines of lesser demand, say 1.8-horsepower-per-cubic-inch, as an example, choosing heads by port volume can work. This is effective for most traditional head designs we know, such as, Chevy big block, 23- and 18-degree small-block. However when you move into the raised-runner custom casting and machining on high-end race builds, it’s time to trust your chosen cylinder head professional.

EngineLabs: Then what does the professional do to select the right head? There must be some formula that involves port volume or flow-bench results to support the decision — it can’t be just experience or intuition?

Airflow and port volume numbers are not the only considerations when working with high-end applications like Pro Stock.

Boggs: Typically it will depend on the level of the build. Today most moderate-level builds are using off-the-shelf-style CNC heads and can base their choices off the tried and true methods. Engine size and rpm will dictate the mass airflow demand of the shortblock. That airflow can be calculated back up the induction system to find what head flow and cross sectional area is needed. This math has been readily available and there are programs to help, like PipeMax. As long as the shortblock cfm demand is met, the velocity management is far more importent the just a flow number. The more specialised the builds become, the more difficult it is to work out the proper induction system. For more demanding style builds, most professional engine builders will consult with their chosen cylinder head professional.

EngineLabs: Finally, please reveal the applications for the port designs you used in the example earlier. That is, a port with a large opening that tapers down to the valve, and a port that is just the opposite — small opening that opens up to the valve. What specific applications would support those intake-port designs?

Boggs: The applications for port areas can be difficult to explain in general terms. In an induction system you are managing pressure differentials. You have several high-differential areas, starting with the venturi in the carburators, perhaps a large port opening in the manifold tapering smaller to a small area where it meets the head forming another venturi. Then there’s the final venturi at the valve. How you manage the relationship between these areas can have various effects. Small areas for quick throttle response or low rpm acceleration, like sprint cars or dirt late models. Larger areas for lighter cars or very high rpm applications with 5-speed transmission, like NHRA Pro Stock. Managing these things are what can give your build its “personality,” that is, very wide, broad power bands versus short and peaky power.

Interesting things happen when you combine ingenuity, good old hot-rodding, and a CNC mill just sitting there begging to turn blocks of billet into chips and artwork. A great case in point are the Granatelli Motorsports “super tall” LS valvecovers we’re using on Project BlownZ. Designed specifically to clear tall valve gear like Jesel’s shaft-mount rocker arms without the use of a spacer, these billet aluminum covers are available with rocker oilers (Part number VC-0081), or without (Part number VC-0081X) like ours.

Concealed beneath our Granatelli covers are Jesel shaft mount rockers that require plenty of extra clearance.

Granatelli’s optional oiler-equipped valve covers are set up to provide additional valvetrain cooling and lubrication from an external oil supply.

For those needing extra valvetrain cooling and lubrication, the versions with integral oilers have removable jets, and both versions are set up with enough material front and rear to add -8 AN breather fittings for dry sump scavenging setups. These super tall covers join Granatelli’s tall LS covers, also available with (PN VC-0019) and without (PN VC-0018) integral oilers, and a tall cover sans-oilers, but offering integral coil mounts instead of the smooth-top setup (PN VC-0017). Finally, for those looking for a standard height cover with coil mounts, there’s Granatelli’s part number VC-0016.

No matter which you choose, you’ll get a super-clean billet look, top quality mounting hardware, and a factory-style O-ring seal. We’re very pleased with the design and quality of our covers, which offer a step up in strength and style from the fabricated covers typically used with valvegear that requires extra clearance. Plus, the one-piece billet construction means no warping or flex as the covers go off and on for between-rounds maintenance, providing a consistent leak-free seal.

The intense specialization in today’s premium engine building demands collaboration throughout the entire process. Crankshaft manufacturers need to know who’s casting the block and pumping the oil. Piston designers need to know what’s under and above the crown. And intake manifold fabricators definitely need to know the intricacies in the cylinder head.

Such a cooperative effort was essential to plan out the specifics for a new engine that will power the Blown Z 275 drag-radial project vehicle. The goal is a supercharged 400ci powerplant capable of 1,800 horsepower. Since induction and airflow is key to horsepower production, the obvious starting point for the discussions focused on the cylinder head and intake manifold.

RFD has proprietary CNC programs for machining the combustion chamber and cylinder head ports from the base Edelbrock casting.

“Everything is custom these days,” says Curtis Boggs of the Virginia-based Race Flow Development (RFD). “We’ll talk to the customer to get the basics of the build, such as engine size and rpm range. Then everything is modified for the customer’s application.”

“We talked to Curtis quite often on this project,” adds Nick Doll, an airflow specialist at Wilson Manifolds. “I need to know the head’s true flow potential, the primary choke area, expected horsepower at rpm and general sizing of the head.”

“I do work closely with Wilson,” echoes Boggs, who supplied a set of “manifold heads” for mockup purposes at the Wilson shop. “They’re very much on their game, and we’ll discuss port sizes.”

LSX race engine foundation

The engine is based on a GM LSX block from Pace Performance and will be assembled by Late Model Engines (LME) in Houston. Internals include a Callies billet 3.75-inch stroke crankshaft, 6.050-inch GRP aluminum connecting rods, 4.125-inch Diamond pistons (10:1 compression ratio), Total Seal rings, ARP fasteners and Clevite bearings. The bottom end consists of a Dailey pan and 6-stage dry sump while the 60mm Comp roller cam will be turned by a Jesel belt drive. Other short-block components include SCE copper head gaskets, an ATI damper, Jesel lifters and pushrods, Fel-Pro gaskets and a TCI starter. In the car, the engine will be sparked by an MSD ignition and exhaust gasses will be routed through Kooks headers.

Here are closeups of the combustion chamber and ports following the CNC machining at Race Flow Development. Note the MoldStar bronze valve seats.

Here are overall views of the intake and exhaust sides of the completed head. RFD doesn’t release flow numbers as they don’t always tell the complete story of managing airflow. Based on the Edelbrock Victor Pro Port LSR casting, the head features the GM SB2 valve-cover footprint.

Strong selection of port designs

“I have six different port combinations for the intake and exhaust on the Edelbrock LS-R head,” explains Boggs. “And from those port combinations I can cut to six or seven different sizes on the CNC machine. We can really customize the head down to the smallest detail.”

From the outset, Boggs knew the engine would be boosted with a ProCharger F1X turned by a Chris Alston reverse-gear drive.

“But it’s kind of limited since they’re not running the biggest blower possible,” adds Boggs. “So you start making considerations for that; such as, you don’t put in the biggest exhaust port. You still have to size them correctly as bigger isn’t always better.”

The heads will be assembled with Ferrea titanium 2.250-inch diameter intake valves and Super Alloy 1.600-inch exhaust valves. The combustion chambers are designed to be as small and efficient as possible at 52cc.

The CNC-machined, lightweight titanium intakes are heat treated and stressed relieved in addition to being treated to a propriety chrome nitride (CrN) coating that helps provide an insulating barrier to high temperatures and helps dissipate heat along with protecting the valve-guide surfaces.

“Even with dynamic forces and valve-flex stresses in a boosted engine, there’s no delaminating or flaking,” says Ferrea’s Zeke Urrutia.

The intake valves feature a 6.350-inch long, 5/16-inch diameter stem and a hardened tip, which negates the need for a lash cap. The Super Alloy exhaust valves measure 1.600-inch diameter and come with a 6.300-inch long, 11/32-inch diameter stem. All 16 valves are radial grooved and have .300-inch tip heights with hardened tips, which negates the need for lash caps. On the advice of Boggs, Ferrea cut the exhaust valves with a .080-inch margin and a 50-degree seat (.0600-inch width). The intake valves were cut with a .060-inch margin and 55-degree seat (.060 -inch width). There’s also a 35-degree back cut (.060-inch width) on the intake valves. These cuts will match up with the MoldStar bronze seats that Boggs installs on the heads.

“On a high-boost engine, you don’t put a 60-degree seat because it’ll tear it up,” warns Boggs. “Valve sizes are based on the pressure differential you’re dealing with. If you have a 12-71 screw blower, that will create a tremendous amount of cylinder pressure and you have to exhaust that. It’s not only the boost level but the volume you’re moving. Valve size itself is not the magic number. Valve sizes are in direct proportion to the throat and port area.”

Working with boost

“Limited ProCharger motors are a little different,” Boggs continues. “They’re not moving the same volume as a screw blower, so you tend to modify the valve and port sizes because you’re dealing with different volumes. Even F1X combos will be up against the max flow of the blower as a limit, so efficiency of the entire combination is just as important as a naturally aspirated combination.”

Some notching on the valve-cover rails is required to clear the pushrods, and the head is machined for a 1-piece Jesel rocker stand.

Boggs works off a spreadsheet he’s built over 35 years of porting head that matches up different combinations to help calculate the port and valve sizes.

“It’s not as simple as putting numbers in a program and that’ll tell you the right cross-sectional area,” explains Boggs. “It’s much more complex than that. Now we get into something I discuss a lot with the customer, and that’s the engine’s personality.”

Boggs offers a scenario where a 355ci engine from a dirt-track late model is compared to a 355ci drag-race engine. The latter requires high-rpm power to get the car down the track through gearing. The late model has to come off the corner with strong mid-range power and provide plenty of snappy throttle response for the restarts.

Considerable work was performed on the Chevy Performance LSX-DR casting to achieve the desired runner lengths and plenum volume. Since the DR casting is made for a different bolt pattern, the original flanges cut off with a bandsaw, then the runner ends were milled with a 45-degree cutter to provide a chamfer that will mate up with a groove in the custom flange.

“The cylinder heads on those two identically sized engines are absolutely opposite. Even if they’re both going to make peak power at 8,000 rpm, they’re going to take drastically different cross-sectional areas and valve sizes.” explains Boggs, who stresses the need to design different mach or air-speed indexes, as an example.

With the ports shaped and sized for the boost levels, Boggs next focused on the combustion chamber where he has a simple maxim: keep it as efficient as possible.

“You see in the industry a number of different combustion chamber designs,” offers Boggs. “For a ProCharger combo I tend to do it with piston design. In this case, we’ve got a small, very efficient combustion chamber. Obviously, you want to direct the combustion over the center of the connecting rod as much as possible. You don’t want side loads on the pistons. A nice, conical dish in the piston tends to center the charge.”

Teaming with Wilson for intake manifold

Boggs uses CNC machines to shape and size the ports and cut out the combustion chamber, which ended up at 52cc. Information on the latter will be given to the piston manufacturer to ensure proper compression ratio. Boggs also works with the customer on cam profiles to complement the airflow.

“This is a custom shop, so I don’t like to just sell a set of heads and make the customer figure out how to run them,” adds Boggs. “We’ll work with cam specs and give feedback on other engine factors. A large part of RFD is professional race-team consulting.”

Of course, teaming with the intake manifold supplier is just as critical, especially when working with boosted applications or situations where rules play a major role in the engine design. For Blown Z, that partner is Wilson Manifolds out of Ft. Lauderdale, Florida.

Note that the welder wears gloves while positioning the manifold on the flanges, which are bolted to the heads. The manifold was treated to 350-degree oven to help prevent warping during the TIG welding process. Immediately after the final weld, the manifold is returned to the engine and covered with a heat blanket, again to reduce the chance of rapid cooling and warpage. Not only is the manifold welded to the new flanges, but additional metal is built up around the runners. After cooling, the manifold goes back to the mill to ensure the ports come in at 4-degrees from the flange.

“If the head has limitations, we might be able to compensate with manifold design,” says Doll. “That’s the kind of things we’ll discuss with the cylinder head specialist.”

Wilson started with a Chevy Performance manifold (PN 19257851), which was obtained from Pace Performance. This casting is designed for the LSX-DR cylinder heads and needed some surgery to fit the Edelbrock heads as well as match the flow characteristics of the RFD porting.

“It was the easiest choice but it’s still not long or wide enough,” explains Doll.

The obvious concern was the unequal runner lengths between the middle and outside cylinders. Wilson technicians first shortened the length of the outside runners by 1.5 inches to help equalize the airflow.

Top left photo is the stock GM casting, followed by photos showing the scars from where Wilson cut and welded to enlarge the plenum and reduce the length of the outside runners. After the fabrication is complete and all the welds are ground and polished, the ports, plenum and other openings are covered. The manifold is then sand-blasted (bottom right) to give the finish a cast appearance.

Equalizing the runners

“When you shorten the outside runners, you also get a larger plenum,” says Doll, “which was also the effect we were going for.”

The next step was cutting off the bolt flanges and prepping the manifold to be welded to a new set of custom mounting plates, which were cut with chamfers around the ports. The ends of the manifold’s runners were also cut with a 45-degree tool to match the chamfers. Before welding, the new plates were bolted to a set of similar LSR heads on mounted on a dummy block, and the manifold was heated in an oven to help prevent warpage during welding.

Additional hand grinding gave the ports and plenum their final shapes and sizes.

“When the manifold mates up with the new flange, the weld will penetrate completely through,” explains Doll. “If we didn’t put that 45-degree V and left it flat, the weld may look good but then when we grind it could cut into air pockets.”

The new flanges will be sized slightly smaller than the head’s intake ports, giving Wilson flexibility in machining the final size. The ends of the manifold runners are also beefed up with additional material.

“All that weld is to make sure that when we get the right transition angle into the port, the machining is not breaking through on the manifold,” says Doll. “Since this is a one-off piece, we’ll do it on the mill.”

The welds are ground flush and polished for a smooth appearance. All external openings are then taped off before the manifold is subjected to the sand blaster to disguise the welds and also provide a fresh-cast appearance. Final prep work includes hand porting the runners.

“The first thing we look at is rpm range and cubic inches,” says Doll. “Even though the inside and outside runner volumes will be slightly different on this manifold, they will have a same taper.”

Wilson will also finish off the interior surfaces with standard 80-grit abrasives.

Manifold runner surface choices

“With fuel injection you can make it a little smoother,” adds Doll. “But even with fuel injection, there are still pulsations. There’s still fuel running around inside that manifold. You don’t want a mirror finish.”

The fuel system includes an Aeromotive pump pushing VP Racing Fuels Q16 race gas to 225-pound Billet Atomizer fuel injectors, so Wilson machined out the manifold runners to install new fuel-injector bosses.

The fuel-injector bosses were machined down, then new bosses were welded at the desired angle. Final work included positioning the fuel-rail supports.

“You look at the approach angle of the head and the valve angles when positioning the bosses,” explains Doll. “You try to aim the injector right at the back of the valve. You don’t want the fuel to hit the wall or floor, then you end up with puddling.”

During the buildup the manifold will also be treated to Wilson fuel rails and a Wilson 123mm V-band throttle body. Controlling the fuel delivery once the engine is installed into the Camaro will be a Holley Dominator ECU.

Check back often for additional stories as LME assembles and dyno tests the engine with a goal of surpassing 1,800 horsepower.

Here is the finished intake with the fuel rails installed. Note both the exterior and interior finishes as well as the fuel-injector location and the final port and plenum shaping. Click on any photo for an expanded view.

If you have been following along at all (we know if you have or have not, kinda like Santa Claus), then you would know that we recently went through the process of building the bottom end of our 440 cubic-inch behemoth small-block dyno mule. The 440 is based on a Dart SHP block with a 4” stroke and 4.185” bore. The Dart block is the foundation for what will become a serious piece of test equipment, one that will sure ingest copious amounts of fuel and nitrous. Before any of that debauchery can happen, however, we need to finish building the engine.

The 440 short block was buttoned up with an ATI Super Damper

Playing Catchup

We have the rotating assembly handled with goodies like the forged Lunati crank and I-beam rods, now we need the soul of any engine- the camshaft. The cam is where all of the magic happens inside an engine. Sure, the crank is big and strong, it takes the abuse from explosions of fuel, pressure from boost and nitrous, but it only does that one thing.

The cam on the other hand is delicate; it doesn’t take much to wipe out a cam lobe, even the wrong oil. The camshaft controls the beat of the engine, how it sounds, how much power it makes.

The beauty of it is that the cam profile is easily changed, unlike the rest of the internal parts. One thing is for certain, the 440 is going to see quite a few different cams. For the baseline, however, we have spec’d out a nice little number from Comp Cams. Because a traditional small-block is 400 cubes or smaller, off the shelf cams are specified for those engine sizes, not exactly optimum for a 440 cubic-inch engine. That required us to depart from the catalog and order a custom grind.

We opted for a custom Comp hydraulic roller bumpstick with .579” of gross valve lift on the intake and exhaust sides with .381 of lobe lift, with 254 degrees of intake duration and 266 degrees on the output side of things. Loads of lift and the long duration mean that this should be one grumbly little small-block in the dyno cell. Since the 440 will likely see numerous cam swaps, we installed a 2-piece timing cover from Comp Cams. Not only does this aluminum cover eliminate flex that can cause erratic timing, but also makes for easy cam swaps without having to deal with the oil pan seal, which is quite nice for a test mule.

No cheap gaskets here, only the best with Fel-Pro's silicone gaskets

Dampening Our Spirits

Hanging off the front of the timing cover is an ATI Super Damper (917411) to settle all those nasty little harmonics that ping off the internals as they spin wildly at 6500 RPM. As we discussed in Part 1, there are all kinds of brutal forces happening inside the engine on the rotating assembly. At any given moment, the crank is pushing a piston up, pulling a piston down all the while another piston is pushing the crank down on its power stroke. This creates crankshaft twist; it robs power and breaks stuff. The damper is there to help absorb the torsional twist.

A poorly built or worn out damper will not absorb any of the twist, but a properly designed damper can absorb virtually all of it. The stock damper is designed to handle just that, a stock engine; it simply cannot handle a modified rotating assembly. Another issue with stock-style dampers is that they can come apart. We opted for the ATI SFI-approved damper for the 440 because the last thing we want is a stock-style damper to explode in the dyno cell.

Each of our cylinder heads were fully machined in the CNC machine shop, including a multi-angle valve job for superior flow.

Before final assembly, the piston to valve clearance was checked with clay

Getting A Head

The next part of the equation is the cylinder heads. The goal here is to make 550hp or more without boost or nitrous, so we need flow to generate that kind of power. When you start with 440 cubes, the power comes in pretty quick without much effort, but you still need the ability to get the air/fuel in and out of the motor in a hurry. Where the camshaft determines the attitude of the engine, the power potential is in the cylinder heads. If we were to stick a set of 291 “double hump” heads on this thing it would run, but not well. We needed a set of lungs that will not only make the 550hp baseline, but also help us test the other parts with reliable results. To do this, we selected a pair of Dart Pro 1 series small-block heads.

There are several versions of these heads, determined by the size of the intake port volume. Since we have a mammoth 440, we went with the equally large 215cc model. Dart does make a larger port SBC head, so why not choose it over the smaller volume? The answer is less than simple, but without getting too technical, here it is—a large port volume will yield more air flow, but at the cost of port velocity. One of the key components of building power is not only pushing as much air/fuel into the engine as possible, but also doing so quickly. This is where many beginners go wrong, they choose a head that is simply too big for the engine and power range they are going for.

The Dart Pro 1 heads were secured to the block with ARP head studs

We mounted a set of Comp Cams Magnum roller rockers. These steel rockers actually weigh less than most aluminum rockers.

Port velocity is the speed at which the air flows through the head. The larger the port volume, the slower the air will move because it doesn’t have to; tighten up the volume and you can flow almost the same amount of air, but it will be moving faster. According to Dart’s website, a projected horsepower range from 500-550 will require between 200 and 220 CC of port volume. Less volume will choke the engine, more will bog it down. These do not necessarily apply to boosted engines, as the air is forced into the engine, not relying on vacuum and atmospheric pressure. The valves on the Dart Pro1 heads are 2.05” intake and 1.60” exhaust, featuring a multi-angle valve job in the intake seat to increase the flow.

Each head is CNC machined to exacting tolerances to ensure each head will match side by side. In as-cast trim, the Pro 1 215cc heads flow 276 cfm @ .600” lift @28” of water, which should provide enough air for our 440 to breathe. We stuck with the 72cc combustion chambers to keep the 440 pump-gas friendly with a 10.1:1 compression ratio, which is one of our main goals.

Dart's aluminum single plane intake is specifically designed to mesh with Dart heads without massaging the ports

The intake was mounted using ARP stainless steel fasteners. We also tried out a few phenolic carb spacers

Top End Reflections

The cylinder heads were mated to the 440 block with a set of Fel-Pro head gaskets between them. Securing the heads is a set of ARP head studs (234-4301). If you have never used head studs, we highly recommend them, they are so choice. Unless you have an 80s GM G-body with AC and need to the pull the heads with the motor in the car. Then you will be cursing yourself. Just sayin’.

Before we torqued the heads down for the final installation, we laid some clay out on the #1 piston, set up a pair of rockers on the #1 cylinder and slowly turned over the motor. Once we had gone a full rotation, we pulled the head to check for valve clearance. This is a crucial step.

We tried a couple of carbs, but ended up sticking with the ProForm 850

Even though we knew that all the specs were dialed in for the theoretical application, you should always check this because it is much easier to fix it now than it is after you hit the starter and frag it all because a valve nicked a piston.

At this point, the valve train could be completed. We went with a set of Comp Cams Magnum roller rockers and roller lifters (190-195-210 and 98891-16, respectively) to compliment that sweet custom camshaft we installed earlier. The valvetrain is an easy place to gain or lose power, so choosing the right parts is critical. The stock rocker arm is a stamped steel POS, so when you are talking about high horsepower numbers, those are automatically out. Reducing friction is the fastest way to gain power, because friction means heat and heat kills everything.

In the valvetrain, “roller” is the key. In this case, roller means roller bearings. Bearings reduce the friction between moving parts. Roller rockers come in two flavors: roller tip and full roller.

Roller tip rockers have a standard trunion (the part that rocks on the rocker stud) with a roller on the, you guessed it, tip, where the rocker meets the valve stem. This reduces one friction point as well as provides a more consistent footprint on the valve. Full roller rockers have needle-bearing trunions and roller tips. Then there is the whole steel vs. aluminum debate on rocker arms.

In the past, aluminum rocker arms got a bad rap because aluminum requires more meat around the bearings, which limits the size of the bearings. This leads to premature failure, where the rocker could literally split in half.

We capped off the 440 with a ProForm 850 cfm carb and a Mallory distributor

Comp Cams has developed aluminum rocker arms that use precision needle bearings that can withstand 350 ft lbs of spring pressure. They are so sure of their aluminum rockers (called Ultra Golds) that they provide a lifetime warranty on each set. Weight is important in a rocker arm because of the moment of inertia. This is the rocker arm’s resistance to rotation.

As the moment of inertia increases, more valve spring pressure is required to control the rocker arm (as opposed to the valve). This robs horsepower and RPM. Reducing the weight on the rocker, particularly away from the trunion, reduces the moment of inertia. In the end, we decided to go with a set of Comp’s Ultra Pro Magnum steel rockers.

These bad boys are made of 8650 chromemoly with strengthening ribs (to help cut the weight) and feature a sporty black oxide finish that resists corrosion. These steel rockers actually weigh a little less than the Ultra Gold aluminum rockers due to their unique webbed design. Because they are steel, there is also a little more room for valve spring and retainer clearance.

The 440 was plumbed and wired to the dyno cell, just about time for some power pulls.

To The Nth Degree

Once the rockers were installed, the Dart assembly team bolted on the degree wheel. Any performance engine camshaft should be degreed. There are numerous influencers on the accuracy of the cam timing; degreeing takes those factors out of the equation, ensuring the valve timing events occur when they are supposed to. Influencers include camshaft variance, timing chain stretch, crank keyway variance, and dowel hole alignment, and can serve to alter the cam timing.

To properly degree a camshaft, you need a degree kit that includes a degree wheel, dial indicator and base, piston stop, checking springs and the pointer. There are two main methods of degreeing a cam, the centerline method and the .050” lift method. Most builders agree that the .050” lift method is the most accurate, and because we are talking about checking accuracy in the first place, that is the method we used.

Topping off the heads is a Dart single-plane intake (42411000) which was designed to work specifically with the Dart heads. The intake runners are matched to the cylinder heads, so that you have optimum flow potential with as few bottlenecks as possible. The intake comes with bosses at all four corners for equalized coolant flow, which is a cool feature in a street/strip car. When used, this allows the coolant pressure to be equalized between the cylinder heads and helps to eliminate air pockets that can make cooling an engine impossible.

Another neat feature of the Dart intake is the dual distributor hold downs, one on each side, making timing changes nice and easy. We sealed the intake to the heads using more Fel-Pro gaskets and a set of trick ARP stainless steel bolts.

The bolts look great and have 12-point heads, so they don’t strip out and you don’t need a big socket that gets in the way, just a 3/8” on a wobble joint and you have no problems reaching the center bolts.

We filled the motor with a little break-in oil from Comp Cams and used a cordless drill to pre-lube the oiling system. Even though we are using a roller cam, it is still a good idea to use proper break-in oil with extra ZDDP to protect the internal parts on the initial start-up. Then the slick cast aluminum DART-emblazoned valve covers were installed, held in place by, yup, more ARP stainless steel fasteners. We also bolted on a water neck so the coolant doesn’t just spill out on the floor.

On The Dyno

On top of the intake we mounted a ProForm 850 CFM carburetor direct to the aluminum. During the dyno test and tune, we will be trying out some spacers, but for now, this carb is ridin’ commando. Another classic gearhead mistake is running too much carb. Even though the 440 is in big-block cubic inch territory, we don’t need a massive carburetor, at least not yet. This mule is naturally aspirated; it doesn’t need massive amounts of air to make plenty of power. Part of that is in the cylinder head design, and the camshaft profile, it just isn’t necessary for what we have planned.

There is always room for improvement. Using the dyno results, the team was able to make some timing and jet changes to extract the most power

There is a simple formula that makes it easy to choose the right carb size (cubic inches x RPM X volumetric efficiency)/3456 = CFM. Volumetric efficiency is the red herring here, but in general terms (VE is expressed in percentages, 100%=1, 90%=.90), a stock motor will be in the .8 range, a performance motor in the .9 range and a boosted engine will be above 1. We have seen naturally aspirated street/strip engines at the dyno push out 110% efficiency, so there is some room for error in the initial calculation without dyno numbers showing the actual efficiency.

The VE limit for a naturally aspirated engine is 137%. We are going to peg our 440 at 95%, which is a realistic number. If we punch in 440 x 6500 (that’s our redline) x .95 and divide that by the magic number (3456), then we see that 786 CFM will do the trick. If the engine turns out to be less efficient, 800 CFM be needed, but that is what tuning is for.

With that, we dropped in the Mallory Comp SS distributor (4248211) and hooked it all up to the Westtech dyno cell for the initial break-in and a few test pulls. After several test runs, we set the distributor to 36-degrees of total timing, no spacer, and the 850 carb. The 440 made good numbers, already hitting our desired spec and passing it by 20 ponies for a total of 570.3 @6200 RPM, while spitting out 545 tire-smoking ft lbs @ 5000 RPM.

So, What’s Next?

Is there more power lurking deep inside the Dart 440? What is it going to take to get 600 out of this plus-size small block? There is definitely more to come from our new dyno mule, we know that for sure. With everything this little monster has inside, we’re figuring on ramping up the numbers with a solid camshaft, lifters and maybe even some more carburetion.

Oh, who are we fooling? We went ahead and did a shootout between our current setup and a solid roller and race carb setup HERE. Trust us, you’ll like what you’ll see.

While so much of the automotive industry wants to make you think that the LS is taking the world by storm, we love that our old school small block Chevy can make some serious horsepower using some really unique and forward-thinking components from Dart, Lunati, Comp and ATI. We’ll be regularly flogging our little powder keg again and again, so make sure to key an eye out.

Building the ultimate engine requires a lot of work, but thanks to a number of offerings from companies like Racing Head Service (RHS), getting the initial setup for your monster LS engine is painless. With the new RHS LS Aluminum Race Block, we found all the features we wanted to start our build, and what’s better is these features exceeded GM’s offerings for their LSX engines. On top of that, we secured ourselves a set of RHS’ LS7 Pro Elite heads that make building a beast of an engine that much simpler. Check out some of the amazing features this awesome block and heads combination from RHS has to offer in the video above.

RHS LS Aluminum Race Block

When it comes to our engines, we like to go big and with Late Model Engines building us a 500ci engine right now, we couldn’t go wrong with the RHS LS Aluminum Race Block to start. This block is made of A357 T6 aluminum for lightweight durability- so durable in fact that it can withstand extreme horsepower outputs. Other features of this block include Siamese cast bore walls with press-in extra long liners for standard and tall deck applications, a GM LS 6-bolt design, CNC porting, factory motor mounts, and larger main cap surface areas to support high-horsepower builds, including those for existing race applications.

Inside the RHS LS Race Block, you’ll find that the camshaft line has been raised for long stroker applications, which is perfect for our 500ci monster currently in the works. The block also comes with an improved priority main oiling design, which increases the overall efficiency of the engine as well as makes it compatible with dry sump systems. The block even features provisions for piston squirters for improved cooling and lubrication-perfect for boosted applications.

LS7 Pro Elite Heads

When building a potent engine like we are, it’s important to find the perfect cylinder heads that can not only support your intended horsepower ratings but also provide an adequate building block for other components. That’s what makes the LS7 Pro Elite heads from RHS so great. Not only will they fit on the RHS LS block or factory LSX engines with their traditional GM LS 6-bolt design, they also make it easier to matte any type of LS7 valve train setups and intake manifolds to your build.

This is due to the unique raised intake runner design that features a 0.220-inch raise for a better line of sight into the cylinders which allows for a better short run than with other LS7 heads.

In addition to the raised runners, a 12-degree valve angle helps increase flow capability within the heads.

The LS Pro Elite heads also feature increased clamping capacity for better head gasket retention no matter how much horsepower or boost you’re throwing at them, as well as reinforced solid rocker rails for increased valve train stability while providing extra clearance for aftermarket rocker setups.

No matter if you’re looking to build a small or large cubic inch engine, the RHS LS aluminum block and LS7 Pro Elite cylinder heads provide a perfect platform for any build. For more information about these products, be sure to visit RHS’ website, and stay tuned for more coverage of the 500ci engine Late Model Engines is building for us using these RHS components.

When we decided to piece together our stroker mill we could have chosen the venerable 454ci big-block using a traditional 4-bolt main Gen IV foundation. This setup would have provided us with lots of low-end grunt at a fraction of the cost. However, we were after something more unique to set this build apart from the rest.

We chose the 502ci foundation because of its proven potential on the dyno, LS-style reliability and although not the most affordable, definitely worth the extra cost and street cred. “The 502 CID LSX engine build exemplifies the design criteria that we set out at RHS for the LS block. It provides a long-arm friendly, large cubic inch combination that incorporates the features of an all-out race block but is suitable for street,” added Kevin Feeney, Product Manager for RHS.

While the majority of our cost went into the short-block alone, we were far from done. When we last left you, we had just finished putting together our big-inch, LME-built RHS 502 short block. We began with RHS‘s new LS tall-deck block, fortified the bottom end with a Lunati rotating assembly and locked it all together using ARP fasteners. We even added as set of high-compression Wiseco slugs to the mix for potent and reliable means for battling the constant high rpm and abuse.

Unfortunately, we couldn’t fit the entire build into one complete story. If you missed the first part of the build, be sure to check it our right HERE. For ease of viewing, we split the build into two parts. This month, we are finishing up by completing the top-end assembly.

While this specific engine embodies a ton of late-model race components, it’s not a race engine. Instead, we plan to put this gem on the street. That said, drivability needed to be key with this particular combination.

The RHS 502 short-block anxiously awaits its top-end assembly.

Coming Together

To achieve this, we finished our build with a set of heavy-breathing RHS aluminum LS7 cylinder heads. Our set was CNC-machined and was equipped for a hydraulic roller camshaft from COMP and came complete with oversized, Ferrera valves (2.20/1.61-inch intake/exhaust valves) and 69cc chambers.

We then matched it with a FAST 102mm LSXR manifold to maximize low- and mid-range torque. Of course, The FAST manifold has also proven itself to carry the horsepower through the upper powerband, making it ideal for our needs.

To see how we did, we headed over to LME and continued our work with Brian Neelan who hooked up our mill to their Superflow 902 engine dyno. We knew it wasn’t going to be record breaker, but we were still impressed by the final numbers. You’ll have to read on to get the complete breakdown of what it made and how we built it.

COMP Lifters

When it came to our long-stroker generating an ample amount of rpm without much work, we went with a hearty set of COMP’s, short travel race hydraulic lifters. COMP Cams has taken a strong foothold within the LS market and produces an abundant supply of LS-related parts and components. We chose these hydraulic lifters because they have been specifically engineered from a patent-pending design which allows them to perform at higher engine speeds.

How is this possible? COMP has designed each lifter to limit the movement of the internal piston from each lifter. Limitations within the internal piston of the lifter cuts down on loss of power and limits valvetrain failure at sustained, high rpm. For a durable and long-lasting life, each lifter is REM-finished and then black oxide coated. We dropped each set into the lifter bores with the T-bars and began assembly of our LS7 cylinder heads.

LME installed each lifter with care before the cylinder heads were placed.

RHS Pro Elite LS7 CNC-Ported Cylinder Heads

With so many cylinder heads claiming superiority in the LS-market, it was hard to choose a set of heavy breathing lungs with the capability and R&D backing what we were looking for. We not only needed a set of cylinder heads to flow well but wanted something that could go on just like a factory cyinder head. We decided on a set of RHS’s new Pro Elite LS7 CNC-ported cylinder heads.

These are truly the aftermarket’s first high performance, LS-style head. These gems also feature a 12-degree valve angle and unique, 0.220-inch raised intake runner design, which provides a better line of sight into the cylinders and allows for an improved short turn. The best part, these cylinder heads also facilitate both the stock and aftermarket LS7 intake manifolds and nearly any aftermarket valvetrain setup.

When speaking with Kevin Feeney over at RHS about our options he gave us the skinny, “The use of our LS7 head is just another testament to how hard our engineers work. They provide the engine builder with the power they expect while leaving them with the convenience of using factory rocker arms and intake manifolds.” 

Bryan Neelan, engine builder at Late Model Engines shared this sentiment and added, “The RHS heads showed strong flow numbers with a nice port shape. I like the volume of the intake runner for the bigger cubic inches the RHS tall deck block accommodates. The RHS cylinder head is a nice clean casting that machines well and was very nice to work with.”

Each cylinder head utilizes the popular LS 6-bolt head design which allows these cylinder heads to be compatible with both the RHS LS race block like we’re using or the GM LSX blocks. The 6-bolt design provides strength and an increased ability to clamp at high capacities, which greatly improves head gasket retention. Most notably, the raised runner and rolled valve angle increases overall flow capability while an improved water jacket design improves thermal conductivity.

While we’re getting eager to get this set of cylinder heads installed, it’s also important to note that these RHS Pro Elite LS7 CNC-ported lungs can be used in small or large cubic-inch hardcore street applications.

For the correct compression, LME knocked off 0.018-inch of material for 63cc chambers.

LS7 Quick Notes

• 100% CNC-machined runners optimize volume, atomization, and velocity
• Increased clamping capacity greatly improves head gasket retention in high horsepower and boosted applications
• 0.750-inch thick deck surface increases integrity; reinforced solid rocker rail increases rigidity and stability
• 355-T6 aluminum withstands race conditions
• 0.400-inch raised rail works with aftermarket rockers
• 0.100-inch raised exhaust port allows use of stock and aftermarket manifolds
• Can be used in both small and large cubic-inch hardcore street/strip applications

Intake & Exhaust

Although we opted out of receiving a completed set of cylinder heads, completed versions are still available and highly recommended from RHS. To control our intake and exhaust flow to our exact specifications, we relied on a custom set of Ferrea titanium intake and stainless steel exhaust valves.

The Ferrea titanium intake valves measured in at 2.200- x 0.313-inch stem with a 5.565 x 0.290-inch tip (hard tip with no lash cap).

The quality of our Ferrea custom titanium and stainless steel intake/exhaust valves compliment the rest of this high-end build.

The titanium benefits our valvetrain from shedding unnecessary weight, essentially freeing up more power for a rev-happy engine. For the exhuast side of things, Ferrea built us a custom stainless steel set which measured in a 1.615- x 0.313-inch stem with a 5.595- x 0.290-inch tip rounding out a complete Ferrea utopia for our intake/exhaust setup.

“Engine valves exert enormous influence on engine airflow, mixture quality and the ability to run higher engine speeds,” says Zeke Urrutia of Ferrea Racing Components. Less mass inertia allows a reduction in valve-spring rates and puts less strain on the entire valvetrain. Titanium valves must be used with bronze valve guides.

Ferrea valves have a proprietary Chrome Nitride coating (CrN) or a diamond-like coating (DLC) to provide rapid heat dissipation and wear reduction while reducing delaminating and flaking from valve flex. Titanium valves generally do not have hardened tips, so they must be used with steel lash caps to prevent damage.

To assemble the rest of our cylinder heads, we used a complete set of COMP components, which included dual springs, titanium retainers, locks, Viton seals with steel jackets and machine steel cups. Install height was 1.820-inch with 145 lb seat pressure with 485 lb at 0.660-inch lift. LME also utilized a 0.150-inch retainer for seal clearance.

Make sure to check out the build list below for all of the cylinder head part numbers. Once LME had each set of cylinder heads together, we could begin the process of installing each one over the ARP 2000 Pro Series head studs and Fel-Pro MLS-style 6-bolt, 0.040-inch head gaskets.

LME assembled our RHS Pro-Elite LS7 cylinder heads using a combination of Ferrea titanium intake with stainless exhuast valves. Additional COMP components were used to finalize the cylinder heads.

GM LS7 Intake & Exhaust Rocker Arms

Once the cylinder heads were locked into place, we could move on and begin installing the RHS rocker stands to each bank. With the RHS cylinder heads, the RHS rocker stands are a must. We installed those first and then moved onto dropping in our 8.400-inch COMP push rods.

From there, it was only a matter of installing each, GM LS7 rocker arm for the intake and exhaust valves. What makes using the GM LS7 rocker arm so unique, is the simple fact that these are off-the-shelf components. This not only cuts down on overall cost but it also makes them more available in the event of failure. What’s more, these rocker arms will install easily on our RHS cylinder heads without any modifications.

We ordered up our sets separately since each set is specifically designed for the intake and exhaust valves. However, both come in the same, self-aligning, 1.8:1 ratio and narrow rocker arm body style.

Rocker Arm Trunion Modification

Since our application, again, isn’t the average build, the factory LS7 rockers won’t be able to sustain high-rpm abuse for the long haul. To combat this, we also modified each rocker arm with the COMP Cams GM LS series retrofit trunion kit. This modification was necessary to convert our stock LS series rocker arms into captured roller trunions for this specific application. It also keeps our valvetrain reliable throughout the entire rpm range. The kit includes all the necessary hardware including, the rocker arm trunions, rocker arm bearings, retaining rings and washers.

FAST Intake and RHS Intake Spacers

Continuing to fire away at the top-end of the engine, LME made quick work for the remainder of the installs before we hit the dyno cell. Next, making its way to the engine was the set of RHS intake spacers. RHS intake spacers will allow the use of standard style LS7-style intakes with tall-deck (9.750-inch) LS aluminum race blocks.

The spacers will work with FAST LSXR LS7 intakes, OEM GM LS7 intakes, or any other intake that is designed to work with LS7 heads. The spacers must also be used with LS7-style cylinder heads.

RHS Intake Spacers At A Glance

• Fits LS7-style intakes
• CNC-machined to strict tolerances to fit 9.750-inch deck height blocks
• CAD designed by engineers at RHS
• Lightweight scalloped design provides rigidity and function without adding significant weight
• Includes required hardware and spacer-to-head gasket (intake manifold gaskets are not included)

With the spacers installed, we could move on to moving some serious amounts of air. For this particular application, LME suggested we try out the FAST line of components. LME chose the FAST-developed, 3-piece, polymer intake manifold. This highly-advanced intake manifold means serious business and its constructed from a proprietary advanced polymer material that offers a host of benefits over aluminum aftermarket intakes, including lighter weight and improved strength and heat dissipating characteristics.

Up close and personal, the RHS intake spacers are truly a piece of art.

This intake also features a 102mm air inlet that is perfectly suited to the FAST Big Mouth 102mm throttle body, which we’ll be relying on. The intake is packed full of other features, too, including integrated nitrous bungs and perfect bolt-on fitment that allows for the use of factory accessories without modifications or clearance concerns.

FAST 102mm Intake Manifold At A Glance

• Fits LS7 raised Rectangle port cylinder head equipped applications (LS7)
• Drive-By-Cable throttle body options
• Big Mouth 102mm throttle body (PN# 54102)
• Big Mouth 92mm throttle body (PN#54092) for drive-by-cable applications
• Fuel Rail Options

The FAST LSXR intake manifolds’ 3-piece modular design allows for easy disassembly and porting. This new design gives you the ability to remove individual runners from the manifold for modification. The best part, this intake manifold is 50-state legal and C.A.R.B. approved (E.O.D.-279-8). We’re anxious to see what kind of power this manifold will produce.

FAST shared with us, “When used with a Big Mouth 102mm Throttle Body, the LSXR Intake Manifold produced gains of 16+ horsepower on a near stock LS7 engine and 26+ rear wheel horsepower on a 500ci RHS LS Aluminum Block based engine.”

The combination of a large FAST intake and throttle body should give us plenty of breathing room.

Aviaid Oiling Systems

Buttoning up the remainder of the build included sealing up the bottom-end with a high-quality and purpose-built oil pan. We were well aware of this particular engine’s extra swing from the stroker crank and rpm potential and weren’t going to cut any corners when it came to controlling oil flow and efficient dispersement.

In our case, we contacted John Schwarz, owner of Aviaid, for the full treatment. With oil control of great importance, John recommended their one-piece, Billet Aviaid dry sump oil pan. It’s good to note, since we’re running a 4.600-inch stroker crank, it was also necessary to run a 3/8-inch spacer between the block and oil pan to give us the clearance needed. While the spacer is necessary for our particular stroker application, this may not be the case for your RHS block.

To continue the Aviaid theme, we outfitted the rest of the build’s oiling system with a four stage externally mounted dry sump, which featured a 1.25-inch pressure side and larger, 1.50-inch scavenge. Additional parts included a remote oil filter and Aviaid dry sump oil tank. Of course, we made sure to install the remainder of the miscellaneous oiling system with Aviaid components.

ATI Super Damper

With build progress coming close to an end and closer to our big-inch LS hitting the dyno cell, we still had a couple more things to take care of. Case in point, controlling engine harmonics. As the engine is running, the crankshaft causes vibrations through torsional flex. It’s these vibrations which can shake an engine apart, literally.

Engine dampers also create additional benefits by increasing engine response. As the vibrations of the engine are absorbed, engine response becomes smoother and vital engine components like main and rod bearings endure less punishment; essentially creating a longer life. Controlling these vibrations, especially on a build of this magnitude was of great importance. However, with limited room to run the four-stage Aviaid dry sump system, LME was left with devising a plan to include a method for driving the pump (6-rib belt) while also controlling engine harmonics. ATI and LME created a solution, which included a combination of an ATI steel hub and an ATI aluminum balancer; making our 7.53-inch diameter damper the perfect addition to this build.

ATI Super Damper At A Glance

• The patented ATI Super Damper is the only crankshaft damper designed exclusively for high performance Chevy engines
• Eliminates torsional crankshaft vibrations
• Exceeds SFI 18.1 specs
• Black zinc chromate finished
• OEM equipment on ZZ572 GM Crate Engines
• Tunable, rebuildable, and extremely efficient at all rpm
• Laser engraved 360-degreee timing marks

We’ve made mentions of the ATI Super Damper before on this particular LS build. As LSXtv Associate Editor Rick Seitz stated in a prior news piece, “Our LS mill is assembled with the best of everything and since it’s running a dry sump oiling system, we relied upon an ATI Performance Products Super Damper.” To finalize the damper’s place on the LS engine, we fastened it down with a an ARP LS balancer bolt.

The ATI damper allows this 502 to not only minimize harmonics buts also drives the Aviaid dry sump pump.

FAST Fuel Injection Control Systems/Components

For our tuning needs, it was necessary to point out LME’s use of the FAST XFI 2.0 engine control system. For this build, it was an easy choice. There really is no other ignition control system that allows its users to process, analyze and adjust parameters more quickly.

The C-Com XFI Windows-based software is easy to navigate and features field-flashable capabilities. This allows users to download the latest software updates through email or directly from FAST. These XFI control units also feature Qwik Tune for programming without a laptop. You can pre-program up to four different EFI maps allowing the ability to optimize a setting for daily driving, one for racing conditions, and still another for fuel economy. With on-board diagnostics, EZ test indicator lights, 5-bar MAP sensing and controls, plus enhanced data-logging capabilities and memory helped influence our choice to run this unit for this high-end build.

FAST XFI 2.0 At A Glance

• Built-in wideband O2
• Fully sequential and/or bank-to-bank capability
• Individual cylinder correction
• Fan and fuel pump control
• Dynamic scaling of vectors in 2D and 3D tables
• Torque converter lockup control
• Air conditioning wide-open throttle cutout
• Boost control
• Fuel and oil pressure logging
• Adjustable injector timing
• Multiple ignition strategies

We continued the FAST theme throughout the remainder of our ignition control systems. Maximizing processing capabilities and ease of wiring, LME went with the FAST EFI harness. With clearly labeled connections, it made wiring up our monster LS build quick and easy.

We also included a bevy of additional FAST components including, the FAST MAP sensor, IAC, ACT, Coolant Temp sensor, TPS Switch, Fuel injector harness, FAST 65-lb Fuel Injectors, Oil Pressure Sensor, AIR Temp Sensor and FAST Billet Fuel Rails for LS7 LSXR intake Injectors. Finally, we were ready for the FAST EFI 102mm throttle body. The FAST 102mm throttle body are machined from durable 6061-T6 billet aluminum in precision CNC machining centers. This throttle body will maximize air flow while also creating a well-mannered, street-driven engine.

LME used the FAST billet fuel rails along with 65 lb/hr fuel injectors to feed the big-inch LS 502.

LME Dyno Results

With the RHS 502 finally buttoned up, primed with oil and strapped down to the LME dyno, we could begin our break-in dyno process. The break-in process will allow the rings to properly seat, keep an eye on oil pressure and provide a chance to make sure there are no leaks. LME also took time during the break-in period to check the condition of the oil. If there was any metallic material in the oil, now would be the time to shut it down. However, our oil was clean.

We began our dyno pulls at 4,000 rpm. This RHS 502 stroker makes so much torque down low, pulling the engine down any lower than 4,000 rpm would not be necessary. From there, we kept our pulls short and gradually increased its maximum rpm. All the while, LME was constantly checking air/fuel ratios as well as tuning the FAST EFI software for optimum power.

All said and done, LME made a mind-blowing 27 dyno pulls with the RHS 502. Sometimes the dyno process can be an all day affair and our experience was no different to dial in our beast. LME took their time to perfect the EFI software making absolutely sure the engine was top-notch.

This LME-built powerhouse proved with our initial pulls that this monster could handle whatever we threw at it. After some post examination of the fuel tables and previous dyno pulls, LME decided to continue safely with more pulls. So, what was the RHS 502 producing? After a final pull for all the glory, we were blown-away.

Once dialed in, our RHS 502ci LSX made an impressive 720.3 horsepower at 6,400 rpm and 669.6 foot-pounds of torque at 5,300 rpm.

 The RHS 502 made a very impressive 720.3 horsepower at 6,400 rpm and 669.6 foot-pounds of torque at 5,300 rpm. While this isn’t your typical, backyard build, LME proved that with the right combination of parts anything is possible; even building an LS-backed 502 stroker for the street. Stay tuned, we’ll have this powerplant going into a ’69 Camaro project soon. Be sure to check out our Blank Slate Camaro’s ongoing progress right HERE!

Heavy-breathing, the RHS 502 proves it’s no chump when it comes to dyno pulls.

Parts List // LME 502 Part 2 Build Sheet

Last month we brought you the buildup of the shortblock on our Wild E. Coyote project – a 1,000-horsepower-capable base for the the soon-to-be-turbocharged hot rod we’ve been working with since 2011. Our previous combination had served us well but with nearly 50,000 hard miles on the odometer, not only was our Coyote showing age, but it was tired as well. 

During the short block portion, Rich Groh Racing Engines and JPC Racing put together a killer Coyote for us using the finest in aftermarket hardware, including a set of JE‘s forged slugs, an octet of Manley‘s Pro Billet I-beam connecting rods, and a factory forged crankshaft. Groh applied his engine building tricks to the bottom end in preparation for installing the top end, which is the focus of this article.

Flowing More Air

As Groh had already put together the bulletproof short block, we turned right back to him to provide the port work on the stock Coyote cylinder head castings. “I’ve worked with Ferrea to develop the larger valve size for these castings, as I developed ports for these heads when they first came out. You can’t go any larger without pulling all of the seats out of the head and replacing them all. Going one millimeter larger is sufficient for the stock seats without any issues. Without spending thousands of dollars on new copper-beryllium seats and the machine work to go with it, this is the perfect design.” Groh said.

Left - The four-valve configuration of the Coyote cylinder head allows for an increased valve area within the same cylinder when compared to a pushrod design. Left Middle - RGR Engines ported the stock cylinder head castings for us, working on specific areas to improve flow without hurting velocity. Right Middle - To go along with our brand-new valves, Groh replaced all of the valve guides in the cylinder heads. Right - As described, our Livernois Motorsports spring package dropped right into place with no modifications needed. They will help provide better valvetrain stability at high RPM and under high boost pressure.

JPC Racing offers three different levels of porting, and Groh said, “All of the port design work is done here in-house by me.  I spent probably four months on the flowbench developing port profiles when the heads first hit the market. These valves are ideal in size for what we’re trying to achieve horsepower-wise, and economical enough to work with the stock casting. The head castings do vary quite a bit from the factory and there are areas where we touch and don’t touch due to the factory casting shift, depending upon what stage portwork we perform,” said Groh.

“The most critical place to perform the work is on the short-turn radius and in the bowl. On the stage two stuff, also in the combustion chamber. The cross-section going into the intake is plenty large enough, and you want to keep that cross-section small, especially on a 302 cubic inch engine. The only way Ford is even able to keep the heads working well in the stock application is because they’re controlling the camshafts hydraulically. Improving the exhaust side is the key to making power with these heads. Of course, the custom valve job we perform on the Newen CNC machine is also critical,” he explains. Our long block relies on a set of the RGR/JPC Stage 2 cylinder heads.

RGR/JPC Stage 1 Heads ($2,495.95) Include:

• Exchange Basis Only, Cores Required
• Fully Assembled
• RGR Custom Competition Valve Job On Newen CNC Single Point Machine
• New Bronze Valve Guides (removal of old guides and installation/sizing of new ones included
• New Ford Valve Seals
• Custom Machining of Intake and Exhaust Valves
• Deck Clean Up
• Port Volume 201cc intake, 84cc exhaust
• Max Flow 320cfm Intake, 222 cfm exhaust at .650-inch lift

Stage 2 Heads ($3,495.95) Add:

• Ferrea Oversized 1.500-inch (38mm, 1mm over stock) Stainless Steel Intake Valves
• Ferrea Oversized 1.262-inch (32mm, 1mm over stock) Stainless Steel Exhaust Valves
• Port Volume 202cc Intake, 85cc Exhaust
• Max Flow 337 cfm Intake, 235 cfm exhaust at .650-inch lift

Stage 3 Heads ($3,895.99) Add:

• Port Volume 208cc Intake, 88cc Exhaust
• Max Flow 342 cfm Intake, 249 cfm exhaust at .650-inch lift

All numbers from Superflow 600 at 28 inches of water on a 3.630-inch stock bore. Exhaust flow calculated with a 1 3/4 inch pipe and standard compression.

Although the Comp Cams intake and exhaust camshafts are sold as their NSR (No Springs Required) design, we went ahead and upgraded the springs in our engine so we can turn the engine at higher RPMs without the fear of valve float.

Cam Technology

Billy Godbold and the team at Comp Cams in Tennessee have had a ton of success with various engine customers in the Coyote world, and rather than dig through a catalog and pick out cams that might work, we decided Goldbolld’s input would be most valuable for this portion of the build.

“People think that once you put a turbocharger onto an engine that your port velocities go up. Take an engine that makes 400 horsepower naturally aspirated and 800 horsepower boosted – your first thought is that the air is traveling that much quicker through the port. But if you actually put a speed gun in the port, you’d see that the 800 horsepower engine actually has slower port velocity, and the reason for that is that the air charge is much denser. In a naturally-aspirated engine, the 228-lobe intake camshaft will only support 7,000 rpm – but in a boosted application like this, it will support 7,500 to 8,000 rpm, because the port velocity is slower. The mass flow is a lot higher, but the actual port velocity is a lot lower. Think of it like this -instead of seeing foamy Coke go through the port, you’re shoving a Frosty through the port,” says Godbold.

In our application, the intake cams are part number 191100 and specs are .492-inch of intake lift combined with the 228-degrees of duration on 126-degree lobe separation. The exhaust camshafts are part number 191060 and feature .453-inch lift and 223 degrees of duration – well above the stock 211-degree number and even greater when you take into account that those figures can be moved around via tuning.

Ferrea Valves

In any big-power build like this, deep breathing is an absolute necessity. We also need internal components that can withstand the intense heat a turbocharger can inflict upon them. To that end, we went straight to the valve wizards at Ferrea to discuss the parts that would best fit our application.

Ferrea’s Zeke Urrutia explained, “With multi-valve engines like this, you usually want to stick with a specific size, which in this case is 1mm oversized from stock – the intake valves [PN F2243P] are 38.1mm (1.50-inch) in diameter, and the exhaust valves [PN F2245P] are 32.05mm (1.242-inch) in diameter. The reasons for the larger valves are twofold; on the intake valve you’re increasing flow on the front side of the combustion chamber, and on the back side, you’re allowing for quicker flow out of the exhaust port. By going larger than these sizes, you can get into an area where it can hurt flow due to the induction turbulence.”

The installation of the turbocharger requires the use of specific materials to live under the increased cylinder pressure and heat that the turbo creates. Ferrea specified very particular material in our application. The intake valves are constructed from their VV50 material, which carries a high tensile strength and high heat handling capabilities, with a 1,600° Fahrenheit max capability.

On the exhaust side, Nimonic 90 is used, blended with their Nickelvac N80A material, and this material is also used for its improved tensile strength and the 2,400° temperature handling capability. The various metal blends help to reduce the chances of thermal fatigue from the extreme combustion chamber temperatures our turbocharger will induce.

Our Ferrea valves are crafted from aerospace alloys that are designed specifically to withstand incredibly intense heat. The triple-groove configuration permits the re-use of stock retainers and locks.

Springs

Valve springs and head studs were sourced from Livernois Motorsports, who also provided their exclusive ARP-manufactured main studs for the bottom end portion of the build. Their drop-in spring upgrade [PN LPP50-TVS-1733] is designed to work with all of the factory hardware, which means there is no added cost for special retainers, spring cups, or seals, and they do not require any extra machining. Installed at 1.575-inch, they provide 70 pounds of pressure on the seat and 190 pounds open, and will handle up to .580-inch of camshaft lift. Groh’s trick is to add a slight shim to the bottom of the spring seat to increase the seat pressure around 25 pounds.

Induction

The last two elements to the inlet side of our airflow package came in the form of one of Ford Racing’s BOSS 302 intake manifolds [PN M-9424-M50BR] and a big-bore 90mm throttle body from BBK [PN 18210]. Since our new engine is capable of spinning way past the 7,000 rpm spot on the dashboard dial, adding the BOSS 302 composite manifold was a no-brainer in our application when camshaft selection was taken into account.

Left - Our BOSS 302 intake manifold is one of the production components that has yet to be improved upon by the aftermarket - it handles high-RPM operation with nary a whimper. Right - Check out the difference between the stock throttle body on the left and our huge-by-large 90mm BBK unit on the right.

The BOSS intake features straight-shot, short runners that have been tuned for a 7,750 rpm power peak, which will mesh well with our camshaft selection. As original equipment on the BOSS Mustang, the intake’s performance has been well documented on the track with everything from street going BOSS 302 models to the Ford Racing 302S and R road-race models. The composite design has been tested to 30 psi of boost pressure and should serve us well.

Thanks to the Mustang’s drive-by-wire design, the BBK Power Plus throttle body carries a bit more complexity than in years past. The electronics are mounted on the side and the integral drive motor is housed internally; this all-new 356 aluminum casting is completely CNC-machined and will offer us the ultimate option for our engine. It also comes with a separate tapered spacer to help it match up cleanly with the FRPP BOSS manifold.

On The Outside

With all of the inlet-side parts taken care of, save for our turbo system (which we’ll cover in a future article), we needed to set up our Coyote with a set of exhaust headers. Since the JPC Racing turbo system is designed to match up with factory-exit-location manifolds, the decision was made to look for a set of aftermarket shorty headers to best supply it. JBA Performance Exhaust Company was started in 1987 to provide the aftermarket with smog-legal shorty headers for the Fox-body Mustang, and in the years since has enlarged their product line to cover dozens of vehicles in a variety of configurations.

JBA Cat4ward headers on top, stock pipes on the bottom. Better flow. Period.

After discussion with the team at JBA, the decision was made to use a set of their Cat4ward Shorty headers in a titanium-coated finish [PN 1685SJT]. The headers use a 1.75-inch primary tube and are constructed from stainless steel. They feature a one-piece 3/8-inch thick flange design and are constructed to attach directly to the stock-style collector. On a normal application, the headers provide increased horsepower and torque throughout the RPM range, and offer improved throttle response. The titanium coating will help to reduce the underhood temperature as well while keeping the heat in the tubes, which is of paramount importance for a turbo application such as ours.

The “Extras”

Even though we started with a complete engine. Rick Riccardi at Downs Ford Motorsport was a huge help in procuring some of the ancillary parts needed to complete the build. His knowledge of both OEM and performance Ford parts proved an invaluable resource during this project.

The Ford Racing Boss 302 head changing kit comes with a great set of MLS head-gaskets that will keep our Coyote sealed up.

Riccardi set us up with a Ford Racing Parts BOSS 302 Head Changing Kit [PN M-6067-M50BR], which includes a set of BOSS 302 head gaskets and high-strength 12mm torque-to-yield head bolts, although we’ll be discarding those in favor of our Livernois head studs. The gaskets are constructed from multi-layer steel and will help to keep the cylinder pressure in the cylinders, and the coolant in the water jackets.

We also procured a set of Ford Racing BOSS 302 timing chain tensioners [PN M-6266-M50B]. There’s a recurring theme here in the use of BOSS parts – when the factory gets it right, you don’t need to stray far away. The BOSS tensioners are designed for improved chain durability in high-rpm applications and are even used in the 2013 Cobra Jet engine program. The kit includes the primary and secondary tensioners and their bolts.

ATI Performance Products has been producing engine dampers for decades now, and in the interest of ensuring that our Coyote doesn’t see any unwanted vibrations, we installed one of their standard-dimension Super Dampers [PN 918047] on the nose of Wild E.’s new crankshaft. Our sister magazine Dragzine did an article on the science of vibration damping previously, so we’ll spare you an in-depth conversation on the topic. To put it simply, the single job of the damper is to eliminate torsional crankshaft vibrations induced under normal engine operation, and the Super Damper does an admirable job of it. It exceeds SFI’s 18.1 spec, features laser-engraved 360-degree timing marks, and is completely rebuildable.

Our ATI Performance Products damper retains the serpentine drive for the air-conditioning belt. After all, what good is a thousand-horsepower car in SoCal without A/C?

We topped off the engine with a set of Aeromotive fuel rails and  Injector Dynamics ID1000 fuel injectors that flow 1015 cc./min. at 43.5 psi, which equates to a 96 lb./hr. injector. These have been proven in competition conditions and will do exactly what we need – keep the fuel flowing smoothly into the CNC-ported cylinder heads so that our Granatelli Pro Series Xtreme coils (which we previously wrote about) can fire it off. Granatelli’s coils feature a unique, patented isolator ring that is designed to eliminate electrical noise to the coil, providing it with a cleaner signal.

Injector Dynamics ID1000

Aeromotive fuel rails and Injector Dynamics ID1000 injectors will provide all of the fuel our engine can suck down.

Since fuel injectors are dynamic (never working under just one operating condition but constantly being adjusted and re-adjusted by the ECU), having reams and reams of data at hand are critical to providing a quality product that will perform as advertised. The Injector Dynamics team tests each individual injector in an environment that simulates real-world conditions, including temperature-controlled fuels, in order to provide the information that your tuner will require to properly set up the tune for your car. Once the injectors are tested, they are placed into matched sets that are based on their flow across the pulsewidth range, and this provides excellent cylinder to cylinder accuracy – critical in a turbocharged, street-going application like ours.

Injector Dynamics’ Tony Palo explained, “All of our injectors run through a 30 minute break in process before any modification and testing to ensure the test results are as they will be in the field. Injectors ‘break in’ from new and their characteristics will change. A brand new matched set of injectors will vary after the coil, valve, and seat has been ‘broken in’.”

He continued, “Typical matching is done as a static flow, but that’s not how the injector works; it’s constantly pulsed. The dead time of the injector is considered the response time. The lower the injector pulsewidth is – at idle, for instance – the bigger the dead time is as a percentage of total on time. So you can have something that’s a nice tight match on a static flow test, but it can be 10, 15, 20 percent off at two milliseconds because of a variance in dead time from one injector to the next. Our matching takes place all the way across the pulsewidth range, so when we say plus or minus one percent, that’s everywhere, and that’s the big difference in how we match our injectors.”

The Final Bits

Our Canton Racing Products road-race style oilpan had a couple of additional ports added in – give them a call if you need a beautiful TIG-welded, trap-door-equipped pan – or even a stock replacement.

On the bottom side of the engine, we needed to wrap things up with an oil pan to provide the dino-juice a place to rest on its journey around the engine, and for that we selected a road race-style pan from Canton Racing Products [PN 15-734]. The package features a windage tray and diamond-shaped baffle assembly with four trap doors to keep the oil from riding up the crankshaft under heard driving conditions. We had them customize it with an additional drain-back port for the turbocharger’s oil feed and an oil temperature port to work best in our application.

Of course, with a turbocharged application like this that’s bound to generate quite a bit of heat, we needed to make sure that the Coyote innards and cylinder heads are kept cool. For that task, we looked in the direction of Meziere Enterprises for an electric Coyote water pump.

The WP342S Street Style Electric Water Pump from Meziere features a CNC-machined thermostat housing and is a bolt-on replacement for the factory mechanical water pump. As they did with the original Modular-style water pumps, Meziere incorporated an idler pulley assembly on the front of the pump to ensure that the stock belt routing doesn’t change, but the addition of the electric pump in place of the mechanical one frees up nearly ten horsepower at the wheels. The 55 gallon-per-minute free flow rating means that the pump will supply all the water you need and then some, and the beautiful black finish will look at home on any street-going Coyote machine. 

Meziere’s electric water pump accepts the factory thermostat housing and heater tube, making it a true bolt-in installation, save for a couple of small wiring tasks to provide power.

It offers a stainless steel main shaft with a ceramic high performance seal, weighs in at 9.1 pounds, and comes with all of the gaskets, hardware, and fittings. Meziere’s main man, Don Meziere, remarked, “In our experience, the factory water pumps in the late model applications are not designed for sustained operation above 6,000 rpm. The factory pump works very well at lower RPM, but once you get into the range where we compete with these engines, they are not very efficient.” Since the Meziere electric pump is not RPM-dependent, it doesn’t face any of those issues. The available wiring harness [PN WIK346] provides a Bosch 30 amp relay, connectors, wire leads and a detailed set of instructions for a trouble-free installation. 

Last, but certainly not least, we attacked the appearance department topside thanks to the help of American Muscle with a sweet set of their pre-painted Sterling Gray coil covers that match our car’s paint color. These are OE on the BOSS 302, carry a “POWERED BY FORD” logo, and fit all 2011-2014 5.0L Coyote engines.

Parts Used

• JPC Racing/RGR CNC Stage 2 Cylinder Heads – PN 1295
• Comp Cams Stage II Intake Cams 228 Duration at .050, .492 lift and 126 degree lobe separation – PN 191100
• Comp Cams Stage I Exhaust Cams 223 Duration at .050, .453 Lift and 126 degree lobe separation – PN 191060
• Comp Cams Phaser Limiters – PN 5493
• Ferrea 1.500 Stainless Intake Valves – PN F2243P — 1.262 Exhaust Valves – PN F2245P

  Our long block nearly buttoned-up. After this it’s time for a crate and the shipment back to our Southern California HQ for installation along with the JPC Racing turbo system.

• Livernois Valve Springs, 70 Pounds Closed Spring Pressure, 190 Pounds Open – PN LPP50-TVS-1733
• Livernois 12mm Head Stud Kit – PN LPP50LMHSKIT
• Ford Racing BOSS 302R Head Changing Kit – PN M-6067-M50BR
• Ford Racing BOSS 302 Intake Manifold – PN M-9424-M50BR
• Injector Dynamics 96 lb./hr. Injectors – PN ID1000
• Aeromotive Fuel Rails – PN 14130
• BBK Big Bore 90 mm Throttle Body – PN 18210
• Meziere 55 gpm Electric Water Pump – PN WP342S
• Canton Racing Products Road Race Oil Pan – PN 15-734
• ATI Performance Products Super Damper – PN 918047
• Ford Racing BOSS 302 Timing Tensioners – PN M-6266-M50B
• JBA Cat4ward Shorty Headers, 1-3/4-inch Primaries, Titanium Cermaic Coated – PN 1685SJT

Almost Time For Install

This finishes off the construction of our long-block, and the next step in our project will be to stuff all of this blingy goodness between the framerails of Wild E. Coyote. We’ll be doing that in the upcoming weeks, so stay tuned for the article detailing the engine install, turbocharger system install, and dyno testing of our thousand-horse street stormer.

Casting numbers on the Gen I cylinder heads are cast in the heads where the rocker arms and valve springs do their work.

The GM small block was specifically designed as a compact sized engine to embrace the economical use of iron and to streamline the production process. Part of the design process that was carried through to the Gen III design in 1997 was to create lightweight rocker arms for higher rpm operation, wedge combustion chambers for a broader power band, and deliver 4.4 inch bore centers (from the center of one bore to the center of the next bore).

The first small block with a 4 inch bore came in the ’62 Corvette 327, and it really opened eyes. Featuring the famous double hump marking on the ends of the heads, the #3782461 and #3782461X heads used 1.94/1.50 inch valves. These were commonly called “Fuelie” heads because they were released with mechanical Rochester fuel injection on the stock engines. The only difference between the two casting numbers was that the #3782461 featured 160cc intake port, 62cc exhaust port and the #3782461X had the larger 172cc intake port, 64cc exhaust port.

The double hump heads continued to be a favorite with performance minded enthusiasts into the new millennium.

High performance enthusiasts separated the stock Gen I heads into closed chamber and open chamber heads. By far, the closed chamber factory heads were favored over the open chamber for making power due to the poor burn characteristics and no swirl (quench) inside the combustion chamber of the open chamber heads. 

Chevrolet Performance LS3 Cylinder Head

Small Block Chevy LS Cylinder Heads by Casting Number 

10215339 – LS Small Block V8 1997 346, LS1, aluminum, 68cc chambers

12480005 – LS Small Block V8 2000 LS1, GTZ, aluminum, 38cc chambers, 2.125/1.625 valves, angle plugs

12556743 – LS Small Block V8 1999 325, 5.3L, aluminum, truck, van

12558806 – LS Small Block V8 1997-1998 346, LS1, aluminum, 68cc chambers

12559853 – LS Small Block V8 1999 346, LS1, aluminum, 68cc chambers

12559862 – LS Small Block V8 1999-2000 aluminum, LS, 4.8 or 5.3L

12559895 – LS Small Block V8 2000 325 (5.3L) aluminum

12561706 – LS Small Block V8 2001-2004 325 (5.3L) aluminum

12561873 – LS Small Block V8 1999-2001 364, 6.0L, LS, 71cc chambers, cast iron

12562317 – LS Small Block V8 2001-2004 364, 6.0L, LS, 71cc chambers, aluminum

12564241 – LS Small Block V8 2000 346, LS1, aluminum, 68cc chambers

12564243 – LS Small Block V8 2001 346 (5.7L LS6) or 364 (6.0L LS2), aluminum

12572035 – LS Small Block V8 2001-2004 364, 6.0L, LS, aluminum, 71cc chambers

12550592 – LS Small Block V8 1997-up 346, LS1

12559846 – LS Small Block V8 1998-up 346, LS1

12560621 – LS Small Block V8 1998-up 346, LS1

12562174 – LS Small Block V8 1998-up 346, LS1

LT1 Small Block V8 cylinder head, casting number 10125320.

10106178 – LT Small Block V8 1990 350, LT5, Corvette ZR1, DOHC 32-valve, aluminum, passenger side head

10106179 – LT Small Block V8 1990 350, LT5, Corvette ZR1, DOHC 32-valve, aluminum, drivers side head

10125320 – LT Small Block V8 1994-1996 350, LT1, cast iron, Caprice 9C1 Police, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling

10128374 – LT Small Block V8 1992 350, LT1, 53cc chambers, angle plugs, aluminum, reverse flow cooling, 175cc intake ports, 68cc exhaust ports

10174389 – LT Small Block V8 1991-1995 350, LT5, Corvette ZR1, DOHC 32-valve, driver side, aluminum

10174390 – LT Small Block V8 1991-1995 350, LT5, Corvette ZR1, DOHC 32-valve, passenger side, aluminum

10205245 – LT Small Block V8 1993 350, LT1, aluminum, reverse flow cooling, 175cc intake ports, 68cc exhaust ports

10207643 – LT Small Block V8 1994-1996 350, LT1, aluminum, reverse flow cooling, 175cc intake ports, 68cc exhaust ports

10208890 – LT Small Block V8 1994-1996 265, Baby LT1, L99, cast iron, reverse flow cooling

10225121 – LT Small Block V8 1994-1995 350, LT5, Corvette ZR1, DOHC 32-valve, drivers side, aluminum

10225122 – LT Small Block V8 1995 350, LT5, Corvette ZR1, DOHC 32-valve, passenger side, aluminum

10239902 – LT Small Block V8 1996 350, LT4, aluminum, reverse flow cooling, 195cc intake ports, 54cc chamber, angle plugs

12529742 – LT Small Block V8 1995-1996 265, Baby LT1, L99, cast iron

12551561 – LT Small Block V8 1996 350, LT1, aluminum, reverse flow cooling

12554290 – LT Small Block V8 1994-1996 350, LT1, Caprice 9C1 Police, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling

12554291 – LT Small Block V8 1995-1996 265, Baby LT1, L99, cast iron

12555690 – LT Small Block V8 1996 350, LT4, aluminum, reverse flow cooling

14088526 – LT Small Block V8 350, LT1, aluminum

Small Block Chevy Gen I Cylinder Heads by Casting Number 

10033867 – V8 aluminum, Pontiac 23 degree head, 62cc chambers, angle plugs, 196cc intake ports

The famous double hump cylinder heads, the #3782461 and #3782461X used 1.94/1.50-inch valves. These were commonly called “Fuelie” heads because they were released with mechanical Rochester fuel injection on the stock engines.

10045434 – V8 aluminum, Pontiac 15 degree head, 55cc chambers, angle plugs, raised runners

10051101 – V8 Bowtie, aluminum, 55cc chambers, angle plugs, raised runners, 196cc intake ports

10065202 – 1987-1995 350, truck

10065203 – 1987-1995 350, truck

10065204 – 1987-1995 350

10065205 – 1987-1995 305

10065206 – 1987-1995 350

10065207 – 1987-1995 305

10088113 – SBC350, Aluminum, 58cc, angle plugs, raised runners, d-port exhaust, 1.94/1.5 valves

10093328 – V8 Pontiac 15 degree head, aluminum, 224cc intake ports, 61cc chambers

10110810 – 1991 350, 65cc chambers

10120928 – 1987-1995 350

10134352 – V8 Bowtie, 45cc chambers, angle plugs, low port, 223cc intake ports, aluminum, 18 degree race head

10134363 – V8 Aluminum, 18 degree or 15 degree, Bowtie race head.

10147898 – 1995-1998 350, crate engine

10159550 – 1987-1995 350

10159551 – 1987-1995 305

10159552 – 1987-1995 350

10159553 – 1987-1995 305

10185040 – V8 Bowtie, aluminum, 45cc chambers, symmetrical ports, 263cc intake ports, splayed valves

10185040 – V8 Bowtie, aluminum, 45cc chambers, symmetrical ports, 240cc intake ports, splayed valves

10239906 – 1996 350, Vortec 5700, L31, 64cc chambers, 170cc intake ports, 1.94/1.5 valves

12367712 – 1999 Fast Burn, aluminum, 210cc intake ports, port, 2.00/1.55 valves, 62cc chambers

12367713 – 1999 ZZ430 crate engine, aluminum, 210cc intake port, 2.00/1.55 valves, 62cc chambers

12480011 – 1997 Bowtie SB2.2, aluminum

12506450 – 1987-1995 350

12509859 – 1987-1994 305

12516852 – 1987-1995 350

Casting number 25534421.

12552520 – 1997 305, Vortec, truck

12558059 – 1997 305, Vortec, truck, 1.84/1.5 valves

12558062 – 1998 350, L31 Vortec, truck, 64cc chambers, 1.94/1.5 valves, 170cc intake ports

14008856 – 1979-1981 267

14010201 – 1982-1985 305

14010516 – 1980-1986 350

14011034 – V8 Bowtie, cast iron, 64cc chambers, 184cc intake ports, angle plugs

14011049 – Bowtie, aluminum, 55cc chambers, angle plugs, 180cc intake ports

14011083 – 1955-1986 350, crate engine, 285hp or 300hp, 64cc chambers, 1.94/1.5 valves

14014415 – 1980-1985 267 or 305

14014416 – 1980-1986 305, 1.84/1.5 valves, 58cc chambers

14014440 – 1980 305, 1.84/1.5 valves

14019821 – 1980-1986 350

14019924 – 1979-1981 267

14019926 – 1980-1986 350

14020517 – 1980 350

14020555 – 1981 305

14020556 – 1981 350

14022056 – 1985 350

14022206 – 1980 350

14022301 – 1980-1986 305

14022601 – 1980-1986 267 or 305, 1.72/1.5 or 1.84/1.5 valves, 53cc chambers

14022801 – 1980-1986 305

14024816 – 350, 76cc chambers, 1.94/1.5 valves, crate engines

14034806 – 1978-1982 267

14034807 – 1978-1986 305

14034808 – 1980-1986 350

14034808 – 1996 350, 76cc chambers, 1.94/1.5 valves, Goodwrench crate engines

14034810 – 1980-1986 350, truck

14034811 – 1980-1986 350, truck

14039121 – 1981-1986 305, truck

14039122 – 1981-1986 305, truck

14071114 – 1980-1986 350

Casting number 19300955

14075381 – 1980-1986 350, truck

14079261 – 1986 350

14085844 – 1980-1986 350, truck

14085963 – 1986 350

14089119 – 1986-1988 350

14094093 – 1986-1988 350

14096217 – 1955-1986 350, crate engine, 285hp or 300hp, 64cc chambers, 72 degree or 90 degree center intake manifold bolt angles

14101081 – 1987-1995 305

14101083 – 1987 350, crate engines, 285hp or 300 hp, 64cc chambers, 72 degree center manifold bolt angles

14101128 – 1986-1987 350, aluminum, 58cc chambers, angle plugs

14102187 – 1987-1991 305, 1.84/1.5 valves

14102191 – 1987 350

14102193 – 1987 305 or 350, 1.94/1.5 valves

1816887 – 1963 283, GMC HD truck

22542525 – Dart or Olds or Chevy aluminum, 14 degree or 17 degree race head

24502559 – 1996-1997 Bowtie, SB2, 1st version, mirror ports, aluminum, 196cc port, CNC version, 280cc intake ports, 38cc chambers

25500141 – Buick or Chevy aluminum, 10 degree race head, 42cc chambers, symmetrical ports, 235cc intake ports, 2.1/1.625 valves

25534351C – 2004 Bowtie, cast iron, Vortec, 175cc intake ports, 65cc exhaust ports, 2.00/1.55 valves

25534371C – 2004 Bowtie, cast iron, Vortec, 206cc intake ports, 77cc exhaust ports, 2.00/1.55 valves

330545 – 1973 350, 76cc chambers, 2.02/1.60 valves

333881 – 1974-1975 350, 76cc chambers, 2.02/1.60 valves

333882 – 1974-1980 350 or 400, 76cc chambers

33417369 – 1990 350, Goodwrench crate engine, 76cc chambers

340292 – 1970 replacement, angle plugs, 64cc chambers

354434 – 1975-1979 262 or 267 or 305, 60cc chambers

358741 – 1976-1979 305

3636839 – 1955 265

3703523 – 1955 265

3713358 – 1955-1956 265

Casting number 3795896

3713569 – 1955-1956 265

3725306 – 1956 265

3731539 – 1957 283, 283hp, mechanical fuel injection

3731544 – 1957-1961 283

3731554 – 1957-1962 283

3731556 – 1957 283, truck

3731762 – 1956 265, Corvette

3737775 – 1962-1967 283 or 327

3740997 – 1957 283, carb or fuel injection, not 283hp

3743056 – 1958 283

3743096 – 1962-1967 327, GMC Truck

3747363 – 1957-1961 283

3747460 – 1959-1967 283 or 327, 70cc chambers

3748770 – 1958 283

3748772 – 1958-1961 283

3755537 – 1957-1962 283

3755539 – 1958-1962 283

3755549 – 1957-1962 283

3755550 – 1959 283

3755585 – 1962-1967 327, GMC Truck

376445 – 1977-1985 350, 76cc chambers, small valves

376450 - 1975-1981 262 or 267 or 305. 6 or 7 exhaust bolt holes, 60cc chambers

3767460 – 1959-1960 283

3767462 – 1962-1967 327

3767465 – 1959-1961 283

3767754 – 1959-1961 283, 60cc chambers

3767792 – 1960-1964 283

3774682 – 1960-1964 283 or 327, 70cc chambers

3774684 – 1962-1964 327, 75cc chambers

3774692 – 1958-1964 283, 60cc chambers

3782461 – 1964-1966 327, camel hump, no accessory holes, 160cc intake ports, 62cc exhaust ports, 62cc chambers

Casting number 3795896. Manufactured from 1963-1965 on 283 Cubic Inch engines. Called the “Power Pack” cylinder heads. 1.72˝ intake valves and 1.50˝ exhaust valves. 60cc Combustion Chambers.

3782461X – 1960-1963 283 or 327, camel hump,no accessory holes,larger 172cc intake ports, 64cc exhaust ports, 62cc chambers

3795896 – 1963-1965 283, 60cc chambers

3795896 – 1962-1964 327, 60cc chambers

3798996 – 1963-1967 327

3814480 – 1960-1967 283 or 327, 70cc chambers, 1.72/1.5 valves

3814482 – 1962-1967 283 or 327 or 350, 75cc chambers

3817680 – 1963-1967 283 or 327

3817681 – 1962-1967 327

3817682 – 1961-1962 283

3836839 – 1955 265

3836842 – 1957-1967 283 or 327

3837064 – 1956-1962 265 or 283

3837065 – 1955-1956 265, truck

3848720 – 1957-1958 283

3876775 – 1960-1967 283 or 327, 75cc chambers

3884520 – 1960-1967 283, 60cc chambers, some used by Studebaker

3884520 – 1962-1967 327, 60cc chambers, some used by Studebaker

3890462 – 1966-1967 302 or 327 or 350, camel hump, no accessory holes, 64cc chambers

3901068 – 1987-up 350, crate engine, 285hp, 64cc chambers

3911032 – 1968 307 or 327, 70cc chamber

3912264 – 1958-1962 283

3912265 – 1963-1964 283

3912311 – 1965-1967 327

3912313 – 1965-1967 327

3917290 – 1967-1968 307 or 327

3917291 – 1967-1968 302 or 327 or 350, camel hump, no accessory holes, 64cc chambers

3917292 – 1968 327 or 350, camel hump, 64cc chambers

3917293 – 1967-1968 307 or 327, 75cc chambers

3927185 – 1969-1976 307 or 327 or 350, 70cc chambers

3927186 – 1969-1970 302 or 350, camel hump, 64cc chambers, has accessory holes

3927187 – 1969-1970 350, camel hump, 64cc chambers, has accessory holes

3927188 – 1969 327, 74cc chambers

3927188 – 1970 307, 74cc chambers

3931633 – 1968-1973 307

3931635 – 1968-1976 350

3931638 – 1968 327, truck

3932441 – 1969-1970 350, 76cc chambers

3932441X – 1969-1970 350 or 400, 80cc chambers

3932454 – 1969-1973 307

3932454 – 1969-1979 350, truck

3946812 – 1969 350

3946813 – 1969-1979 350, truck

Casting number 12529093

3947040 – 1968 327, 64cc chambers, truck, no accessory holes

3947041 – 1969-1970 302 or 350, 64cc chambers

3947041X – 1969-1970 302 or 350, 64cc chambers, 165cc intake ports

3951598 – 1970 400, 76cc chambers

3964286 – SBC 350

3965742 – 1970 350, replacement, angle plugs

3970126 – 1967-1971 327 or 350

3973370 – 1969-1970 350, 64cc chambers, straight plugs or angle plugs

3973414 – 1970 350, LT1, 350hp or 370hp, camel hump, 64cc chambers

3973487 – 1971-1972 350, 1.94/1.5 or 2.02/1.6 valves, also 1971 350 or 330hp LT1, 75cc chambers

3973487X – 1971-1972 350, 1.94/1.5 or 2.02/1.6 valves, 75cc chambers

3973493 – 1971-1972 400, 76cc chambers

3986316 – 1971 350, 76cc chambers

3986336 – 1971 350, 76cc chambers

3986336X – 1971 350, 76cc chambers

3986339 – 1971 307 or 350, 74cc chambers

3986339X – 1971 307 or 350, 74cc chambers

3986388 – 1968-1976 307 or 350

3991492 – 1970 350, LT1, camel hump, accessory holes, 64cc chambers, straight plugs

3991492 – 1970 camel hump, 64cc, straight plugs or angle plugs

3998916 – 1972 350, 1972 350 LT1, screw in studs, 76cc chambers

3998920 – 1972-1973 350

3998991 – 1972-1973 307 or 350, 75cc chambers

3998993 – 1972-1973 307 or 350, 75cc chambers

3998993 – 350, Goodwrench crate engine, 75cc chambers

3998997 – 1972-1973 350 or 400, 76cc chambers

3998997 – 1978-1984 305 or 350, 76cc chambers

4079261 – 1975 350

458642 – 1975-1984 350, 350

462614 – 1977-1979 305, 60cc chambers

462624 – 1975-1986 350 or 400, 76cc chambers, 1.72/1.50, 1.94/1.50 or 2.02/1.60 valves

468642 – 1976 350 or 400

471513 – 1979 267 or 350

517513 – 1979 267 or 350

It’s no secret that Chevy’s LS engines are good breathers, so when you force-feed one with a few pounds of boost, its output sprouts like Godzilla’s vegetable garden. Stock, production-vehicle engines are generally capable of handling the boost delivered by basic bolt-on blower kits – anywhere from 5-8 pounds, which typically adds about 100-120 rear-wheel horsepower.

The components of the rotating assembly are collected and prepped for a series of inspections and measurements to ensure each conforms to the factory specifications. Shown is the forged aluminum piston set, which is used in both the LSX376-B8 and LSX376-B15 engines. When matched with the LS3 heads, they deliver a boost-friendly compression ratio of approximately 9.0:1.

That ain’t bad, but when you’re planning to go after bigger dyno numbers with a high-boost charge, a stronger bottom end is called for because the factory parts simply weren’t designed for that type of performance. We’re going after big numbers to help our new 1978 Malibu wagon project car “Fugly” get down the quarter-mile in the 9-second range. So thus begins the build of our 1,000+ horsepower, Whipple supercharged behemoth Chevy Performance LSX376-B15.

Sure, a Dominator-topped, nitrous-slurping big-block would do the trick, but it’s been done. We’re looking for a challenge and a supercharged LS is the most contemporary way to build big power. And besides, the greater weight balance with an LS power plant – even with an iron block and all the accoutrements of the supercharger – will be a valuable advantage for the nose-heavy Chevy.

We’re going to show you nearly every nut and bolt involved in this project in words, photos and video, starting here with the assembly of one of Chevrolet Performance’s boost-ready LSX376B-series crate engines, which will be foundation for our build-up. After this, we’ll show how the engine responds with a large-displacement supercharger, sneaking up on our power goal with moderate boost and the crate engine’s stock valvetrain. Then, we’ll got nuts with higher boost, a Crane Cams solid-roller camshaft and complementing valvetrain, and maybe some other hardcore parts. We’re looking for 1,000+ horsepower and plan to rely on Holley’s new Dominator EFI system to conduct the air/fuel symphony.

After the dust settles in the dyno room, we’ll drop the engine in our Malibu and go get our 9-second time slip. But first things first…

Left: A custom air gauge is used to measure the outer diameter of each piston. The technician rotates the piston within the fixture and air jets are used to determine the diameter, which is recorded on a master file for the engine. The gauge is calibrated every four hours to ensure absolute accuracy. Right: Another air gauge is used to measure the pistons’ pin bores. In all, there are 15 air gauges used throughout the engine assembly, taking measurements down to 0.00001-inch. Again, every measurement is recorded in a master file for each engine.

Inside the LSX376B Crate Engines

Chevrolet Performance developed the boost-capable LSX376B-series engines a couple of years ago with the express purpose of offering economical long block-style assemblies that are ready to accept the supercharger or turbo system of the builder’s choice. There are two versions – the lower-boost LSX376-B8 (part number 19260831) and higher-boost LSX376-B15 (part number 19299306).

As their names imply, the LSX376-B8 is rated to about 8 pounds of boost and the “B15” is good for about 15 pounds or so. Each uses a mix of purposeful high-performance components and production components, which helps keep down the price. They didn’t skimp where it counts, however, such a forged steel crankshaft on the “B15.” The other important component of each assembly is a set of forged aluminum, low-compression pistons, which are essential for longevity and staving off engine-killing detonation. If you simply bolt a blower onto a production engine, you’ll be dealing with compression of around 10.5 or 11.0:1 – or higher – and hypereutectic pistons.

The LSX376-B15 engine uses the tough connecting rods from the Camaro ZL1’s LSA engine, which were designed from the outset for a supercharged engine.

Left: The LSA rods are delivered to the assembly line as single pieces, then the cap is carefully snapped off, creating a perfect, puzzle piece-like fit when it’s installed on the engine. Right: Like the pistons, each rod is measured with a custom air gauge tool, which measures the small and big ends simultaneously. This one passed with flying colors and is headed for our project engine.

Perhaps just as importantly, the engines use LSX-LS3 cylinder heads, which are based on the high-flow, rectangular-port design of the production LS3 engine, but with a six-bolt head bolt design matched with the LSX block’s six-bolt provisions. It significantly enhances clamping strength for the heads, providing – along with standard multi-layer steel head gaskets – exceptional cylinder sealing under high boost pressure. That’s just what our project engine will see when we get our greasy mitts on the crate engine.

“Chevrolet Performance engineers developed the LSX Bowtie block and LSX cylinder heads specifically for the rigors of extreme performance,” says Dr. Jamie Meyer, Performance Marketing Manager for Chevrolet Performance. “With the LSX376 ‘B’ engines, we’ve created affordable foundations for supercharged or turbocharged power that fit just about every budget. Of course, the blower, fuel system and other necessary components are up to the customer, but with their durable forged components, six-bolt head clamping and lower compression, these engines deliver a lot of boost for the buck.”

The heads also offer tremendous airflow attributes, too, which is just what we want for an engine that will have plenty of air crammed through it. They have rectangular ports similar in design to the LS7 design, with large, 260cc intake ports. The LSX six-bolt castings also feature a little more meat on the bone in strategic areas to support additional port work. We don’t know if we’ll hog ’em out further, but it’s good to know the heads can handle it.

Left to Right: The roller lifters are measured, too – and not simply to confirm their diameters. Out-of-round and taper is measured, as well. With the camshaft, the part number is verified, the part number is recorded in the master file and then the journals are measured with another air gauge. Out-of-round and taper are also determined. With all of the respective measurements completed, work begins with building the rod-and-piston assemblies. A cast iron LSX Bowtie Block with the regular-production 9.240-inch deck height is the engine’s foundation and is delivered to the assembly line already honed and cleaned. After an inspection, it undergoes a wash to remove residual oil or grease and is then blown dry with compressed air. The main bores, cam bores, damper inner diameter and other journals are then measured with air gauges.

We’re also told these crate engines use the latest version of the LSX block, which was revamped recently to improve strength and durability, particularly under boost. That’s an assuring thing to keep in mind as we head for four-digit horsepower territory on the dyno.

Building For Boost

The LSX376B-series crate engines are assembled at a specialized facility in the Detroit area, which blends the best of hand-assembly and production-line techniques. Every component associated with the rotating assembly the respective holes they fill in the block are mic’d with ultra-precise air gauge tools and their specifications recorded in a master file for each engine. Think of it as high-tech blueprinting.

Computer-controlled and calibrated torque wrenches ensure consistency with every engine, too, but they don’t replace the eyes and experience of specially trained builders who guide each engine from start to finish. There are only four stations involved with each engine’s assembly, with a single builder at each one responsible for specific tasks. In the first station, the rotating assembly and engine block are inspected, measured and prepped for assembly. At the second station, the bottom end of the engine is installed and at the third stage, the heads and other top-end parts are added. The final station is an inspection stop, where each engine subjected to a roster of checks, including leaks, compression and oil pressure.

Unlike some other Chevrolet Performance crate engines, the LSX376B-series engines do not come with an intake system or oil pan, which helps keeps the cost down and creates less waste – after all, who needs a production-style intake manifold if you’re going to drop on a 4.0-liter Whipple twin-screw compressor? And with LS engines being thrown into so many different cars these days, what good is a production oil pan that’s just going to be removed or sliced up anyway? We’ll definitely need a custom pan for our Malibu. Custom headers, too – but more on all that in our next installments of this high-boost project.

Until then, check out the photos we took inside the assembly facility and learn more about what goes into these specialized crate engines. We’ll definitely be putting out LSX376B15 to the test soon!

Assembly Photos and Captions

A forged steel crankshaft with a 58X reluctor wheel is carefully lowered into place, but prior to installation, the rod and main journals are measured in four places to calculate out-of-round and taper. Also, the crank’s snout and the damper’s internal diameter are measured to calculate the interference fit.

In goes the camshaft. For our “B15” engine, it’s the LS7’s high-lift hydraulic roller, which has a pretty wide 121-degreee lobe separation angle a hydraulic roller, along with 0.558/0.558-inch lift and 211/230-degrees duration specs.

With the crankshaft and camshaft in place, the roller timing chain setup is installed, after which the high-volume, wet-sump oil pump from the LSA production engine is installed on the crank snout.

The piston assemblies are slide into place after the rod bearing received a coat of oil. Guide tools threaded onto the ends of the rods and a piston ring compressor ensure an easy, damage-free installation. The connecting rod caps are then torqued down to 64 ft-lbs.

With the engine upright, the roller lifters are carefully tapped into place and their respective keepers cinched down.

It takes a lot of pressure to drive on the damper onto the crank snout and a hydraulic cylinder is used for the task. Then, the damper bolt is tightened with a 6:1 gear-reduction tool, because of the high torque rating – 37 ft-lbs plus 140 degrees.

Both the LSX376-B8 and B15 engines use multilayer steel cylinder head gaskets that offer exceptional cylinder sealing for supercharged and turbocharged engine combinations.

The engine breathes through Chevrolet Performance’s LSX-LS3 cylinder heads, which are based on the high-flow, rectangular port design of the standard LS3 head, but with a six-bolt configuration that greatly enhances the clamping strength when compared with production-style four-bolt heads. They also feature large, 260cc intake ports.

The LSX-LS3 heads have 68cc combustion chambers and 2.160-inch hollow-stem intake and 1.550-inch solid-stem exhaust valves. The valves are held at a 15-degree angle.

The valvetrain comes next and includes LS3 pushrods and a set of LS7-style 1.7-ratio rocker arms, which feature and offset design on the intake-side arms. They’re torqued down to 30 Newton-meters.

A valley cover caps the engine and essentially completes the engine assembly. The LSX376 “B” engines are delivered without an intake manifold to make it easier and more economical to accommodate a blower or turbo. And because vehicle installations very so wildly, they’re delivered without an oil pan, too. A dust cover is installed over the crankshaft.

After the engine is assembled, it’s moved to final-inspection station, where it is leak-tested by pumping the water passages with about 20 psi of compressed air. The engine is also primed with warm oil to validate oil pressure and the compression is checked. From here, it will be shipped to our dyno facility, where the next stage in our project will begin with the supercharged installation. Stay tuned!

Some of us just have to look good while going fast. Thankfully, there are guys like JR Granatelli of Granatelli Motor Sports who share that passion. A quick look through his company’s website shows not only a laundry list of go-fast parts, but also a wide range of appearance items that will take your ride to the next level. In fact, Granatelli Motor Sports is expanding with new CNC equipment and manpower to build these covers in the GMS Australia facility. 

These billet valve covers are machined in Australia in Granatelli Motor Sports’ newest facility.

Currently under construction at Late Model Engines in Houston, Texas, is a new 400-cube LSX engine for the BlownZ project car. It sports a set of Edelbrock LS-R heads modified by Curtis Boggs at Race Flow Development. Unlike other LS heads, these castings are designed with an SB2 valve-cover footprint. It just so happens that Granatelli Motor Sports makes an awesome set of billet valve covers for the SB2. 

“These are constructed from 6061-T6 aluminum and are machined from a solid chunk on a CNC machine. What makes them unique is that they are machined in a single-stop process. The entire cover is shaped in one single program – it never stops. If you look at the top, or the bottom, there are no pickup marks where you can see the machine stop,” explains Granatelli.

The one-stop machining process first locates all of the bolt holes, which each step of the machining process indexes from. The bottom side of the cover is scalloped out in one continuous process before the cover is flipped over to machine the top half.

The valve covers are machined in a turning center, which has the ability to do all aspects of the machining operation without a single bit of input from the operator.

“The bottom of the cover is machined first, where the bowl of the valve cover is machined out out, then the turning center flips the cover over and machines the entire top of the cover, all in one process,” Granatelli says, noting the first step of the machining process drills out the mounting holes, which are then fastened by the turning center to index all of the other machining operations. ”These covers, along with the rest of our billet valve cover line, are designed in a computer program called Pro Engineering, or Pro E, before the files are exported to a Computer Aided Design file and loaded into the Haas CNC machine. From there, the machine cuts out each cover.”

The thick gasket rail on the bottom of the covers helps to solidify the cover-to-cylinder head junction, and provides a bit of extra strength to the cylinder head casting, especially in boosted applications.

There are a number of reasons to use a billet valve cover, besides their striking good looks. These covers have optional integral valve spring oilers with removable jets, which will help to keep spring temperatures down and introduce more longevity to our package. In addition, the covers feature steel inserts in all mounting holes to reduce the chance of damage should they be overtightened, or the regular wear and tear that occurs from repeated installation and removal. Another cool feature is the ability to have a custom logo cut into the top of the cover – not a printed logo, but one actually machined into the cover’s face. 

But wait, there’s more! Each cover features a set of strengthening ribs on the underside that help to prevent the tops of the covers from getting sucked down by an overzealous vacuum pump, or pushed out by an engine making tons of boost. The ribs have the added benefit of helping to keep the top of the cylinder head from flexing under boost, which will prove to be helpful in boost applications.

“The cover has the effect of an upper cylinder head stud girdle to make the cylinder head more rigid, and guys like Duttweiler and Lingenfelter are using them on all of their engines that are making big boost,” explains Granatelli.

Left - you can see the bottom side of the cover taking shape, and the strengthening ribs that are cut into the underside. Right - The top side of the cover is also finished in one continuous process - the end result is a beautiful toolpath that catches the eye from all angles.

Jewelry for your engine – and you can have them for most popular engine platforms. Check out the Granatelli website for more information!

For most of the country winter is a time when project cars get tucked away in the garage for refreshing, updates, upgrades, or to start new builds. If you happen to be an enthusiast planning an engine upgrade this winter, Edelbrock wants to offer you a free 75th anniversary jacket when you a purchase any new pair of their cylinder heads.

From December 1, 2013 until January 31, 2014, Edelbrock will once again hold it’s Heads and Threads promotion. Any new pair of cylinder heads purchased during that period as a pair, part of a power package, or part of a crate engine are eligible for the jacket giveaway.

To get the jacket all you have to do is complete an entry form which can be found here, and submit it, along with the UPC barcode from the boxes, and the original receipt, and send it in to Edelbrock before February 28.

The limited edition jacket features a large Edelbrock 75th Anniversary logo on the back, and small Edelbrock logo on the front. The polyester liner has screen-printed logos from several legendary Edelbrock products on it.

So when you’re not out in the garage swinging wrenches, you can keep warm this winter in style with that new Edelbrock jacket. For the latest details on all Edelbrock promotions or how to get your jacket check out the Edelbrock promotions page, and be sure to send in all your paperwork by February 28, 2014.

An engine makes power by moving air and fuel into and out of it. The more of both it can move, and the faster it can do it, the more power the engine makes. In theory it’s pretty simple but in reality it’s  more complicated. There are thousands of factors that effect not only how much air, but also the quality of that air, that gets into an engine. The most restrictive, and therefore the most critical factors, are the cylinder head intake and exhaust ports. That’s why so much thought and design must go into a cylinder head for each application. 

We don’t have room here to illustrate how to maximize a cylinder head’s effectiveness by port design and shaping—that information could easily fill several hard-bound books. Rather, let’s talk about how to measure airflow in and out of a combustion chamber using a flowbench.

New cylinder heads rated by several measurements but one of the most important to consider is cubic feet per minute (CFM) of air that can flow in both the intake and exhaust ports. The CFM rating should be tailored to the engine’s desired flow rate and power level, which could fill yet another book. The flowbench is a tool that lets you check what that flow is. Let’s say you performed a home porting job on your heads (yet another book) and want to see how much, if any, you improved flow. The flowbench will tell you.

As illustrated in the video below, SuperFlow offers a variety of flowbenches to fit the needs of race shops, garages and parts manufacturers. 

“The main reason for the different flowbench sizes is to match the flow requirement of different heads,” sums up Mike Giles, marketing manager at SuperFlow. “You don’t need the highest capacity bench to flow a motorcycle head.”

SuperFlow benches range from flowing up 160 cfm at 10 inches of water to 1,100 cfm at 25 inches. Again, check out the video to learn more about each flowbench.

One of the key features for all but one of the SuperFlow benches is the FlowCom measurement system that does away with manual reading of a manometer. Some veteran engine builders may prefer the old method of watching the water levels, but there are numerous advantages to the new system.

“Some guys don’t trust computers,” says Giles. “They like using manometers because they can see it. From a technical standpoint, the FlowCom is much more accurate.”

http://www.youtube.com/watch?v=hpccoZWWZQw

The main problem with a manometer is that the readings can change depending on the viewing angle of the meniscus.

“That’s especially true on smaller benches where the scale isn’t as large,” adds Giles.

Another benefit of a computerized measurement system is cost.

“Believe it or not, it’s more affordable to produce the FlowCom than use a manometer,” says Giles. “Also, with the computer you get additional features, such as no more lookup tables. The numbers that read out are already corrected.”

Power Automedia recently obtained a SuperFlow SF-750 flowbench for the shop and is already putting it to good use on projects. This story will show how to use it, and then how to interpret the data using the help of Curtis Boggs from Race Flow Development (RFD) in Virginia Beach, VA.

About the SF-750

SuperFlow has several different models of flowbenches, from the compact table-top SF-110 all the way to the full-on professional SF-1020 and 1020-SB Superbenches that have all the bells and whistles, including SuperFlow’s WinDyn Data Acquisition System for advanced testing and data analysis (on the SB model). It flows a whopping 1,100 CFM at 25 inches of water test pressure, making it pretty much overkill for the average guy. The SuperFlow SF-750 outlined here is a great bench for even a big engine shop; SuperFlow calls it “the new standard in digital flow testing, with more capacity than its predecessor, the SF-600, and increased accuracy with digital measurements.” It’ll flow 660 CFM at 25 inches of water and comes standard with SuperFlow’s FlowCom™ digital airflow measurement system for accurate, repeatable and fast testing. FlowCom™ ensures accurate digital airflow measurement and control by automatically measuring test pressure and temperature; then presenting corrected flow data on the easy-to-read, precision display. This saves users considerable time when compared with standard manometer type benches that require users to make calculations to achieve corrected flow numbers. The included automatic motor controller maintains constant test pressure without the use of knobs and valves and it also helps extend motor life by reducing heat generated during operation. Reduced heat means that operators can run the SF-750 for longer durations than benches lacking the motor control feature.

The market for flowbenches is expanding and transitioning. In the early ’70s when SuperFlow launched its first flowbench, most of the cylinder heads were cast-iron and very rough in port design. 

“There was plenty of room for improvement,” says Giles. “Today, with premium CNC-ported heads you’ve got to think twice about taking a die grinder to them.”

Since CNC heads usually have a proprietary design, more engine builders are using flowbenches to validate promised flow numbers and make internal comparisons to help determine cam timing and other engine adjustments. They also flow each port to ensure consistency across the cylinders.

Consistency is also crucial when setting up a test program on the flowbench. Engine builders should establish a reliable A-B-A process and maintain accurate records.

“Where we also see a lot of mistakes is in fixtures,” adds Giles. “Obviously it has to seal or you’re measuring flow that isn’t from the head or intake. It’s just a leak. Also, you want the proper-sized fixtures with no restrictions.”

Here are the main tools to flow a cylinder head. On the right is the billet aluminum main adapter plate that bolts to the flowbench surface, on top of a rubber gasket (far left). On top of the big plate is another plate (second from right) that we’ll call the slider plate. It bolts to the cylinder head and sits/slides on the main adapter plate. A rubber O-ring seals the two. The 4-hole head gasket-like rubber gasket second from left goes between the head and slider for another airproof seal. The main adapter (below left) comes with several sets of different sized sleeves to match the cylinder bore of the engine block that the heads will be used on. This one is 4.030-inch. They have upper and lower O-rings for an airtight seal. The main adapter plate bolts to the bench, but it’s much easier to install a set of studs (below center) to save time and headaches. Note the gasket in place before the adapter is lifted in place and bolted down (below right). It just needs to be snug.

Expert consultation

Curtis Boggs is a well-known cylinder-head specialist at Race Flow Development and is well-experienced in flow testing heads and evaluating the results. Following is EngineLabs‘ one-on-one conversation with him:

EngineLabs: How important is it for an engine builder to own or have access to a flowbench, and why?

Curtis Boggs: Personally, when I’m involved in an engine build I want to have the most data possible. For an engine builder it really depends on the level he/she wants to work on in the cylinder head program. There’s a ton of good data for an engine builder with a flowbench. Once there’s a fair amount of data collected over several builds, it becomes easier to identify trends. A good cylinder head supplier would take some the pressure off of the typical engine builder to log flow numbers. However if the builder uses several different sources for heads it could help with data and identify trends if they did it themselves. It’s important to flow heads from different sources on the same bench with the same technique. Typically when one of my customers, or any engine builder, buys a flowbench, they learn some things very quickly. First, it doesn’t take the huge flow numbers people think to make power or win on Sunday, and a peak flow number isn’t the most important number. There’s a tremendous amount of data for an engine builder. I wouldn’t build anything without one.

The main adapter (below left) comes with several sets of different sized sleeves to match the cylinder bore of the engine block that the heads will be used on. This one is 4.030-inch. They have upper and lower O-rings for an airtight seal. The main adapter plate bolts to the bench, but it’s much easier to install a set of studs (below center) to save time and headaches. Note the gasket in place before the adapter is lifted in place and bolted down (below right). It just needs to be snug.

EL: What can flow numbers tell you about a cylinder head’s performance?

Boggs: Flow numbers by themselves aren’t worth the weight most people give them. Yes, we can calculate the potential mass airflow through the engine, which is great data, but there’s much more data needed to make a good assessment. Port shape, geometry, chamber shape, velocity profiles etc., all play a significant roll in power. Experienced cylinder head engineers can tell some things from a flow chart—the curve can show a head with the port too big or a throat too small, things like that. What happens to the flow after the convergence point tells me a lot about a head. 

The head adapter (which we’ll call the slider plate) also has a selection of sleeves to match the bore size. We call it a slider plate since that’s what it does. It allows you to flow all four chambers on a head without unbolting and remounting it for each cylinder. PowerAutomedia tech Sean Goude marked both plates when the slider plate was perfectly placed over the main bore, to make sure that the flow numbers are accurate and also to speed testing.

The valves are opened manually to test flow, so the valve springs must be changed to low-tension test springs, shown here on an iron head. Also, don’t forget the spark plug as you prepare the cylinder head. Otherwise there will be an obvious leak in the airflow. Make sure to use the “head gasket” when putting the cylinder head on the adapter plate. The head can be installed this way, or by bolting the slider plate to it first then lifting the assembly into place.

EL: Do you personally have a flowbench and how often do you use it?

Boggs: I’ve owned several flowbenches since I started in the mid ’70s, and have even built some. As an induction engineer I have to own one and use it on a daily basis.

This hand screw tightens the slider plate when the chamber is lined up and ready to flow. Superflow includes this billet stand that bolts to the valve cover rail on the head. It mounts dial indicator used to indicate valve opening. During testing, the valve will opened via this dial indicator. Set it up then make sure it has enough stroke to open the valve to the highest point you want to test. In other words, if you have a .700” lift cam and want to test at that lift point, make sure the indicator has at least .700” travel. It’s a good idea to add another .050” for a safety margin. Goude likes to zero his indicator then run it down to .100” and back to zero to make sure it’s right.

EL: When using a flowbench for porting heads, are there different flow numbers you want to look for in applications for circle track, drag racing, street/strip, or the typical musclecar?

Boggs: Well again, it goes past just a CFM number. Too many people think the bigger the number the better, and it’s just not true all of the time! A great example here is the difference between a high rpm drag engine and a circle track engine. Drag engines typically can use larger ports, slower air speeds, and are run under a little more forgiving circumstances than a circle track engine. Big ports and big flow numbers typically don’t make fast lap times in circle track or road race cars. You have got to match the velocity profile of the head to the application. This will effect the peak flow number, so you should be using the flow bench with a velocity probe.

EL: Anything else you can say about flowbenches or airflow in general, beyond what has already been published in Engine Labs?

Boggs: Well, only that I have a reputation for saying that flow numbers don’t matter, and that couldn’t be farther from my intention. Flow numbers are very important—we are working on air pumps basically. However, the other things in a cylinder head like I mentioned earlier are as, if not more, important also. The biggest flow number doesn’t always win.

Before testing, utilize some form of radius to make a smooth transition into the port and an ensure a more accurate reading. Modeling clay works well, and aftermarket suppliers offer premolded attachments. The FlowCom system handles all the math, unlike the old days when readings had to be taken and computed by hand. But first, some settings have to be be made (see below) to the flow bench.

Shown from left: FlowCom touch screen, flow calibration table, flow direction handles and the light switch; Flow Calibration table showing six ranges of adjustment for flow (the closer the actual flow of the port is to these range maximums, the more accurate the resolution); Lever that sets the flow range; Levers to set the airflow direction.

With the flow direction and range handles set, the remainder of preliminary information settings are entered in the FlowCom computer (above). The industry standard for flow testing is at 28 inches of water (below left) and the flow range, which was determined from the calibration table and set with the range handle, must be entered (center photo) along with the flow direction (right photo)

When everything is ready to go, hit the on/off switch and the bench starts working. Open the valve to the desired starting point (most use .050”) by turning the dial indicator adjustment screw (on top) to .050” as indicated on the dial, then continue with each increment after you log the results. A flowbench is loud, like the loudest vacuum cleaner you’ve ever heard, so you might want to consider earplugs. One thing to watch out for is that the modeling clay doesn’t get sucked into the port. To test the exhaust side, you don’t need to flip the head around unless you want to flow it with a header in place. Just change flow direction and run through the computer again with the same routine as used on the intake side.

While the machine is flow testing, the cfm of airflow is shown on the computer screen after “Flow.” In these two cases the flow is 159.8 cfm and 224.3 cfm at valve openings of .300--inch and .600-inch, respectively. Simply jot down the numbers as you flow the head at different valve openings and then make the necessary comparisons to either confirm the airflow performance or help in cylinder head/intake manifold development.

Here’s the original photo comparing the before and after work on a funny car cylinder head.

Was the work fake or authentic?

A few days ago, EngineLabs shared a before-and-after photo of damaged cylinder head on its Facebook page. The photo was originally posted by Noonan Race Engineering on its Facebook page. It was composite showing a closeup a heavily damaged combustion chamber and the finished repair work.

Within minutes, many readers were crying foul and charging that the two combustion chambers were not the same:

• “Not the same head. Pay attention to detail.”
• “Two different heads. Look at the holes are backwards.”
• “Wow, they even moved the spark plug and changed the bolt pattern.”
• “That is not the same head, and yes, I am a cylinder head tech.”
• “Not the same head, guys.”
• “Please tell how they are not the same head.”

Turns out that all the skeptics know less about photography than cylinder-head repair. Plenty of other readers noticed that the head was simply photographed from different sides.

The problem was simply a matter of perception. Noonan had photographed the heads from different sides. EngineLabs used Photoshop to rotate the damaged-chamber photo 180 degrees, and now the bolt and spark-plug holes match up.

Just to be sure, EngineLabs contacted Alan McCoy, operations manager and machinist at Noonan, a racing parts and engineering company based in Queensland, Australia. Noonan is best known for designing the X1 billet cylinder head used by Pro Mod and Top Alcohol racers.

“We find it quite amusing some of the comments that are seen on Facebook,” says McCoy. “The before and after photos that were posted are definitely the same chamber from the same cylinder head.”

The head is not an X1 but rather a competitor’s model used by nostalgia funny car racer Peter Leahy.

What caused the damage?

Cause of the damage is uncertain. McCoy says the usual culprit is bottom-end failure or over-revving. This head was brought in bare, but other times the Noonan technicians have to remove broken valve heads or bent valve stems. The next step is to replace damaged valve guides.

“These are a flanged steel guide with a guide liner inside,” explains McCoy. “If the guide is bent, we machine off the guide and flange down to the head on the valve-spring side with a manual mill and drive out the remaining guide into the port. This way the parent guide bore in the head does not get swaged by the bent guide.”

Noonan Race Engineering is known for its X1 cylinder head used in Pro Mod and Top Alcohol racing.

“Aluminum must be machined back to clean the material,” says McCoy, “to prevent impurities entering the weld.”

The chambers and insert recesses are then TIG welded to repair damage and build up sufficient material in the chamber.

“It’s important not to overheat the material to prevent a hardness dropoff,” says McCoy.

Noonan also designs and manufactures Pro Stock heads, valve covers and intake manifolds.

“If the heads are fairly tired, we generally recommend surfacing the heads .005-inch to .010-inch or so,” sums up McCoy. “Then we can re-machine all chambers and seats back to original heights, restoring the chamber volume to a like new condition.”

Noonan promised to photograph the steps for EngineLabs the next time a similar head case comes to the shop.

TECH5 is a regular feature where EngineLabs asks industry leaders five technical questions. This week’s guest is Richard Maskin, former Pro Stock engine builder and founder of Dart Machinery. 

EngineLabs: How did you address windage problems inherent in the factory LS block when you designed the Dart LS Next block?

The Dart LS Next block combines the late-model performance capability with Gen I-style bottom end.

Maskin: The first LS had problems with oil staying in suspension and not returning to the pan because of the windage in the Y-block design. GM’s first attempt to fix it was making the crank with hollow mains, like a racing crank, which allowed the engine to communicate from bay to bay. Then they put the windows in. When we cut the pan rails of the LS, all the problems were fixable. But windage is the tip of the iceberg. A stock LS engine with any performance value; say, making 600 horsepower at 6,500 rpm, takes 17 to 20 gallons to lubricate engine, of which 10 gallons or more is leaking by bearings, lifters and such. That’s ridiculous. Fixing the windage allowed us to do a lot of other things, like run a stepped main oil galley so we can have both volume and pressure. We’re building the first LX Next engine right now. It’ll have an external oil pump because I believe a stock LS pump would blow the filter off, since we’ve dramatically closed down the amount of oil this engine will need. We’re keeping it in the 7-to-8-gallon range. Also, the iron block is capable of 9.5-inch deck, but because windows are gone the cylinder barrel is longer. So the effective deck height relative to other blocks is 9.875 inches. You can do a lot with that now. The aluminum block will have other features that will allow users to build bigger engines and do it correctly, like raising the cam. We didn’t want to do that to the iron block.

EngineLabs: What is the future of billet blocks, a technology which seems to be driving bore spacings out to 5.3 inches?

Maskin: The rules have set the limit at 5.3 inches, but with billet there are no rules. Billet is limited only by your imagination, so it’s fun stuff. They’re expensive engines, kind of like Top Fuel racing with doors. We’ve been making billet heads with water jackets for 5.2- and 5.3-inch bore spacings. They’re even lighter than castings but stop the failures associated with early castings. We stay busy with billet, but it’s a time-consuming product.

EngineLabs: What are your thoughts on the balance between high air-flow numbers and the “quality” of air flow when designing a cylinder head?

Maskin: We don’t have CFD analysis. We bought a wet flow bench years ago that can flow 500 cfm wet at 80 inches. We can empirically measure air flow, fuel flow, brake specific and color the fuel to watch it with a black light. By moving stuff around at that high of depression on the intake side, it allows you to see things you couldn’t see any other way. We’re watching where the streams of fuel go. It’s very strange what really works and how it looks. It’s actually two big streams not dispersed and atomized, like you think it would be. Also, we’ve found airflow on the intake side is secondary. The cross-sectional area and port shape is primary. On the exhaust side it changes dramatically

Dart founder Richard Maskin

EngineLabs: How so?

Maskin: Think of boosted setups. What’s going to change on the intake side? If anything, we can stand a little more size because it’s pressurized and probably fuel injected, so we can push the fuel and air in the cylinder. On the exhaust side, it’s still normally aspirated. We don’t have a pressure inducer for that, so that makes exhaust even more critical than in a normally aspirated engine. I can’t emphasize how important the exhaust side is.

EngineLabs: Pro Stock continues to run iron blocks, and racers have said you can’t make power with aluminum blocks. Please explain the problems and dynamics in Pro Stock?

Maskin: I don’t think that’s true any more — that you can’t make power with aluminum blocks. In Pro Stock, you’re limited to 4.900-inch bore spacing. Pro Stock engine builders run bores from 4.730 to 4.750 inches. That leaves .150 to .170 inch between the cylinders, and you can’t do that with aluminum. You have to use an iron block for stability. Now if you said, we’re going to have a 4.730-inch bore, keep the 500-cubic-inch limit but go to 5.00-inch bore spacing, then an aluminum block will run just as good. You can take a good CGI block and put a 4.800-inch OD sleeve in it after a miscue and still put a 4.730 bore. That’s only .030-inch per side, but behind it is a really good grade of cast iron. So, it works. With billet, you could probably get away with [4.900 bore spacing], but they’ll never allow billet in Pro Stock.