Gen III/Gen IV Cylinder Head Buyers' Guide

What's Out There For our LS1,LS2,LS6,5.3, LQ9 or Other Late Model Motor.

In the market for a huge power increase? Then you're probably looking at getting a set of ported aluminum heads on your GM car or truck. Here's a sampling of what's available from the aftermarket community. Note that each head is just an example of what that company has to offer, so check their Web sites for a myriad of other heads available as well as possible options for the head listed (such as combustion chamber cc). Compression ratios quoted are for an otherwise-stock 5.7 LS1.

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AFR LS1 Mongoose Street Head
Company: Air Flow Research
Intake cc: 205
Chamber cc: 66
Approximate Compression: 10.2:1

AFR's heads are its own casting, and the Mongoose Street head is no exception. This fully CNC-ported head features the same intake port cc as the stock LS1 head, yet outflows it by over 70 cfm. Fully emissions-legal, this direct bolt-on head features the same .75-inch deck as all other AFR heads for reliable sealing, and also features thick port walls and reinforced rocker stud bosses. Add in AFR's new double-quench pad area combustion chamber, and you have a winner hands-down. AFR's suggested retail price is $2,499. A 76cc version is also available for lower compression applications. If you like to "port your own," an as-cast version of this head is also available and comes without valvetrain parts.

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Edelbrock/Lingenfelter CNC-Ported LS1 Head
Company: Edelbrock
Intake cc: 205
Chamber cc: 65
Approximate Compression: 10.3:1

Relying on Lingenfelter's many years of CNC experience, Edelbrock now offers a new head--its own casting, mind you--that is a bolt-on replacement for all '97-and-later GM V-8s. After being ported by Lingenfelter it is shipped fully assembled, and it includes titanium retainers and COMP Cams valvesprings as well as Edelbrock proprietary valve guides. This head is brand-new, so emissions legality is pending, as is pricing. If you want to do your own porting, an unported version featuring stock dimensions so that any LS1 or LS6 CNC program can be run on it also available.

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ET Performance CNC-Ported LS1 4.8/5.3 Head
Company: ET Performance
Intake cc: 230
Chamber cc: 64
Approximate Compression: 10.5:1

ETP pours its own casting that is different in several ways from other heads on the market. A raised valve cover rail as well as an 11-degree valve angle (versus the factory 15-degree) make for a serious head for serious applications. Intake runners from 215cc up to--get this--255cc in volume are also available, as well as killer C5R heads, all on ETP's own aftermarket castings. Any kind of porting you want is available; you name it, ETP will do it. Check with the company for the latest pricing.

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Patriot LS6-style CNC Heads
Company: Patriot Performance
Intake cc: 227
Chamber cc: 59
Approximate Compression: 11.1:1

Patriot says there are several things that set its heads apart. First, it offers combustion chamber sizes from 59cc to 72cc while maintaining the stock deck height. In addition, these sizes are offered for any bore in the range of 3.90 to 4.125 inches. A choice of valve sizes is available, ranging between 2.02 and 2.08 inches, and the heads come out the door fully assembled with goodies such as titanium retainers, viton rubber seals, and Patriot's own Gold Dual valvesprings. Pricing is $1,195 per pair, assembled.

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GMPP CNC-Ported Gen III Aluminum Racing Cylinder Head
Company: GM Performance Parts
Intake cc: 250
Chamber cc: 44
Approximate Compression: 13.9 to 1

This particular item is a fully machined and CNC-ported C5R head with 2.18-inch intake valves and 1.625-inch exhaust valves. You may as well just ignore the above-quoted LS1 compression ratio because with valves that big, you're going to need a bigger-bore block to bolt these heads to! Call your local GM dealer for pricing on this and other heads available from GM Performance Parts. If you have several-thousand dollars lying around, pick up a C5R block while you're at it.

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HPE Stage 3 4.8/5.3 LS1 head
Company: Horsepower Engineering
Intake cc: 230
Chamber cc: 64
Approximate Compression: 10.5:1

Optimal power and torque is the name of the game with HPE's Stage 3 4.8/5.3 head. Featuring a high-velocity port to maintain good drivability, 40-50 rwhp over stock can be had with these heads. Full Rev valvetrain hardware, such as valvesprings good to well over 0.600-inch lift are included, all for the price of $2,195. Horsepower Engineering also offers a Stage 2 head package for the best "bang for the buck."

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Lingenfelter CNC-Ported LS1 Cylinder Heads
Company: Lingenfelter Performance Engineering
Intake cc: Customer-specified
Chamber cc: Customer-specified
Approximate Compression: Customer-specified

Precision CNC-machined in-house, Lingenfelter offers ported LS1 heads designed to yield improved port velocity as well as high-flow capabilities. This combination gives a strong torque curve as well as high horsepower. Lingenfelter claims that the elimination of hand-porting each and every head provides more consistency from port to port. However, the CNC program itself is derived from an LS1 head that was hand-ported by Lingenfelter, so in effect, you do get a "hand-ported" CNC head that Lingenfelter put many hours into perfecting. Pricing is $1,595 for the above-described units, not including refundable core charge.

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Precision Porting and Coatings Stage 3 LS-series Heads
Company: Precision Porting and Coatings
Intake cc: Customer-specified
Chamber cc: 58
Approximate Compression: 11.3:1

PP&C says its $1,499 Stage 3 head package offers the best possible setup for a street/strip vehicle. Hand-porting gives balanced runners matched to the customers' camshaft profile and driving style. All of Precision's heads (or any head you wish to send in) get their valve faces and combustion chamber coated with their thermal barrier coating, which reduces hot spots and helps to prevent detonation. Precision says customers can expect oil and coolant temperatures to drop significantly thanks to these coatings, particularly during hard driving. A range of combustion chamber sizes is available and 6.0L castings can be used to lower the compression for forced-induction applications.

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FLP Stage 3 LS6 heads
Company: Finish Line Performance
Intake cc: 236
Chamber cc: 65
Approximate Compression: 10.3:1

Ported by Scott Fulkerson of Midwest Engine Tech in Mokena, Illinois, FLP's Stage 3 LS6 heads flow 317 cfm on the intake and 217 cfm on the exhaust, and feature a 2.10-inch intake and 1.60-inch exhaust valves. Pricing for a set of these particular heads is $2,299. You can supply your own head cores or FLP can use its own to minimize your ride's downtime. All of FLP's heads can be milled to achieve a higher compression ratio for a nominal charge. In addition to the LS6ers, LS1 and 5.3 heads can also be used.

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TPIS Stage 2 Ported LS1 Cylinder Heads
Company: Tuned Port Induction Specialties
Intake cc: 218
Chamber cc: 64
Approximate Compression: 10.5:1

TPIS starts off this package with a set of 5.7 LS1 heads and fully CNC ports the chambers and runners, installs 2.02 and 1.56-inch lightweight stainless valves, and puts on titanium retainers and springs appropriate to the customer's camshaft selection. A full three-angle valve job is also performed. The going rate on a set of these heads is $1,700 on an exchange basis. Even larger valves are available if desired, as are porting work on 5.3 and 6.0L cylinder heads.

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PRC Stage 2.5 5.3L Heads
Company: Precision Race Components
(Texas Speed & Performance)
Intake cc: Customer-specified
Chamber cc: 62
Approximate Compression: 10.7:1

Precision Race Components and Texas Speed and Performance are two faces of the same company, so don't get confused. This particular 5.3 head package goes for $1,529 and includes 2.04- and 1.575-inch stainless steel valves. Large valves are available if the customer wishes to upgrade to the Stage 3 package. This company's heads are sold outright as new castings, so no core swap is involved, though Precision Race Components will gladly port castings a customer supplies as well. All heads are hand-finished, bowl-blended, assembled, decked, and flow-tested by a full-time cylinder-head specialist trained by the School of Automotive Machinists.

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SLP AFR Cylinder Heads
Company: SLP Performance Parts
Intake cc: 225
Chamber cc: 62
Approximate Compression: 10.7:1

SLP has teamed up with AFR to bring these CNC-ported street/strip heads to the market. Despite features such as 2.08-inch intake valves and 1.60-inch exhaust valves, they are fully emissions legal--even in California. Flowing up to 320 cfm at 0.600-inch lift, these heads are fully assembled, ready to bolt on, and ready to make power! Like with all AFR head castings, these heads have many high-durability features, like reinforced rocker stud bosses and interlocking ductile iron valve seats. $2,649 makes them yours.

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Race Prep Phase IIILSR Heads
Company: Race Prep Performance Engineering
Intake cc: Customer-specified
Chamber cc: 66
Approximate Compression: 10.2:1

Using factory 6.0L castings, Race Prep's Stage IIILSR heads get their chambers welded, cryogenically treated, and machined to accept larger valves, yielding a more efficient chamber design and 340-cfm flow figures. This is a full race package, and thermal barrier coatings on the chambers and valves can be had as well. This full package goes for $3,675. Race Prep prides itself on offering the customer exactly what they need for their application and not just something "off-the-shelf," and larger chamber sizes are available. The company also offers ported AFR castings that will outflow even the Stage IIILSR heads.

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TEA Stage 1.5 5.3 Heads
Company: Total Engine Airflow
Intake cc: Customer-specified
Chamber cc: Customer-specified
Approximate Compression: Customer-specified

Total Engine Airflow's biggest mover is its ported Stage 1.5 5.3 head. Designed for a 3.90-inch bore, these heads get a blended competition multi-angle valve job, Ferrea 2.02-inch intake valves, and TEA 0.650-inch lift dual valvesprings (COMP Cams springs are optional). The price of $1,575 includes new GM head castings. Choose from stock exhaust valves or REV 1.57 inchers. Or, select from TEA's Stage 1, 2, or 3 cylinder head packages.

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More Performance Profiler
Company: More Performance
Intake cc: TBA
Chamber cc: TBA
Compression: TBA

More Performance's brand-new Profiler head flows nearly 330 cfm on the intake as-cast and can be ported for even higher flow numbers based on a particular engine application. In fact, by virtue of its extra-thick port walls, the head converts into a C5R head; that is, it can be ported all the way to C5R valve angles and flow up to 400 cfm. Other features of the head include raised valve cover rails and dual valve cover bolt patterns for both pre-'99 and '99-and-later applications. Details on this head, including pricing, are still being worked out as of print time, so check its Web site for more information, as well as other products More Performance markets.

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RGR Performance Stage 2 Heads
Company: Speed Inc.
Intake cc: 243
Chamber cc: Customer-specified
Approximate Compression: Customer-specified

Hand-ported by Rich Groh Racing exclusively for Speed Inc., these heads feature 2.02-inch intake and 1.57-inch exhaust valves, along with titanium retainers. A lightweight valve option is also available for a slight charge. Speed Inc. relies on these heads for many of its own projects, as well as record-breaking customer build ups. Though it admits the lead-time will be longer to procure a set of these RGR heads than some of the CNC units offered, Speed Inc. claims the results are always worth the wait. They'll go for $1,799 on an exchange basis.

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Katech Stage III 2.100-inch LS6 Cylinder Head Assembly
Company: Katech Engine Building and Development
Intake cc: 240
Chamber cc: Customer-specified
Approximate Compression: Customer-specified

Katech says the 2.100-inch hollow-stem intake valves are the secret to this head's awesome across-the-board flow numbers. Though they can only be used on engines with at least a 4-inch bore, these heads will provide 330 cfm of flow at only 0.600-inch lift, and their modest intake port volume will preserve mid-range torque. Katech says the countless hours it put into CNC machine programming has resulted in a 100 percent repeatable intake port that cleans up perfectly on the machine and doesn't require hand finishing, thereby assuring each intake port flows identical numbers. Pricing on this head is $2,759.

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West Coast Cylinder Heads Stage 2 6.0L Heads
Company: West Coast Racing Cylinder Heads
Intake cc: 233
Chamber cc: 74
Approximate Compression: 9.4:1

With 2.02 and 1.57-inch valves, West Coast's ported 6.0 heads flow just under 300 cfm at 0.600-inch lift. Its large combustion chamber drops compression for blown LS1 applications. Many custom options are available, and West Coast is constantly updating its CNC profiles to maximize performance in specialized applications. Several other heads are available as a starting point, and coming soon are CNC porting profiles for the new Edelbrock head castings. Please call for the most up-to-date pricing.

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TTP Stage 4R AFR 225cc CNC Heads
Company: TT Performance Parts
Intake cc: 225
Chamber cc: Customer-specified
Approximate Compression: Customer-specified

TT Performance Parts starts off with AFR's 225 CNC heads and does its own special in-house porting job to achieve what the company claims are record-breaking flow and horsepower numbers. A '98 Camaro equipped with one of TTP's Equalizer head and cam packages included a set of these heads and made 505 hp at the rear wheels, even with the stock bottom end. This easily put the customer's previously installed head and cam package to shame. Several other head packages are available, all starting with the solid foundation of AFR heads. Call TTP for current pricing.


SLP Performance Parts
Toms River, NJ 08755
Air Flow Research
Valencia, CA 91355
Total Engine Airflow
Tallmadge, OH 44278
Chevrolet Performance Parts
Detroit, MI 48232
Patriot Performance
Rainbow, AL 35906
West Coast Racing Cylinder Heads
Reseda, CA
Speed Inc.
Schaumburg, IL 60193
Race-Prep Performance Engineering
Bermuda Dunes, CA 92203
Lingenfelter Performance Engineering
Decatur, IN
Tuned Port Induction Specialties (TPIS)
Finish Line Performance
Milford, OH 45150
More Performance Inc.
Charlotte, NC 28208
TT Performance Parts Inc.
Clifton, NJ 07013
Katech Inc.
Clinton Township, MI 48035
ET Performance
Walled Lake, MI 48390
Horsepower Engineering (HPE)
Houston, TX 77086
Precision Porting and Coatings
Hudson, FL 34667
Engines Drivetrain
In the market for a huge power increase? Then you're probably looking at getting a set of ported aluminum heads on your GM car ...
Jan 1, 2006


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