Rectangular port heads boast a clear advantage in the flow department and are ideal for high-RPM, big-cubic-inch, and purpose-built drag racing applications.
Factory castings are capable of 360 to 400 cfm when ported properly, which can make it difficult to justify an aftermarket casting. However, aftermarket castings boast designs more suitable for both more extreme applications and street cars looking for better torque. Factory heads have design compromises for emissions and cost (obviously missing from aftermarket designs) and are optimized for low-lift camshafts and other OEM components. However, the aftermarket can achieve the performance potential of a race head that is compatible with factory intake and exhaust patterns.
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Factory Heads
LS7
These were the first heads to bring race car quality and technology to the OEM side. Although common in the aftermarket, CNC-porting of the intake and exhaust runners is usually too costly for a factory head. Titanium intake valves and sodium-filled exhaust valves were previously unheard of in a domestic factory engine, which revved to 7,200 rpm, another anomaly for a pushrod V-8. Right out of the box, these heads have supported more than 600 hp naturally aspirated and substantially more with forced induction. The large, raised runners and 12-degree valve angle enable substantial flow that supports large cubic inches. And the large valves necessitate a 4.125-inch or larger bore, and otherwise bolt right up with LS7-specific intake manifold bolts. These heads are available at any Chevrolet Performance dealer for around $1,500. (Photos Courtesy General Motors)
L92/LS3/LSA
These mini-LS7 heads debuted in Australia first in the 2006 Holden Commodore (among others) as the L76 and L98, but are most commonly known for their debut on the 2007 Escalade’s L92. Only one significant change was made for use on the LS3 engine in the Corvette, Camaro, and G8 GXP–hollow-stem valves. A better casting was used for added strength on the supercharged LSA, but it is also mostly unchanged since its original inception. Though sacrifices were made for emissions, you won’t find a higher-flowing head for the money. The L92 head was the first to boast 330 cfm while being dirt cheap, which started the craze. The massive intake valves necessitate a 4-inch-or-larger bore with no other special consideration needed. These heads are available for a scant $375 from Chevrolet Performance dealers, making them an excellent bang for the buck. (Photos Courtesy General Motors)
LS9
The formula for building the most powerful factory GM engine ever was fairly simple: Add a supercharger to the LS3 and beef it up considerably. Though they bare plenty of resemblance to the LS3, the LS9 head has a number of features that make them more suitable for boosted applications. The rotocast method (also used on the LSA) and the use of A356T6 alloy make this a stronger casting that is better at handling the added heat generated from a supercharger. The factory CNC porting would seemingly increase flow, but a few changes to the port shape were made to improve swirl that actually decreases flow (but improves over-all performance in a supercharged application). Titanium intake valves and sodium-filled exhaust valves keep it on par with the LS7 and allow the engine to peak at 6,500 rpm. Just like the LS3, the large valves require a 4-inch bore, and the LS9 also has a thicker deck and larger head bolts for better clamping with boost. If you are not using an LS9 block, you need ARP head studs to rectify. The intake manifold locating bosses also need to be machined for use with an LS3 or L92 manifold. Any Chevrolet Performance dealer sells these heads for around $1,120.
(Photo Courtesy General Motors)
Aftermarket Heads
Advanced Induction
Includes:
L92, 267 cc
LS3, 275 cc
LS7, 280 cc
North Carolina–based Advanced Inductions is widely known for CNC head porting, with programs for the Gen II, III, and IV small-block only. Specializing in such a finite area makes AI particularly knowledgable, precise, and efficient. Advanced Inductions offers a plethora of heads with aftermarket and factory castings. It also offers intake manifold porting and valvetrain kits with a specially designed camshaft. (Photos Courtesy Advanced Induction)
L92 267 cc
LS3 275 cc
LS7 280 cc
Advanced Induction
L92, 267 cc
Because the “823” casting already comes with such a large port, Advanced Induction focuses on simply increasing the efficiency and shape of the intake runners. A large portion of the gains, though, come from opening up the exhaust ports. In fact, AI offers a more budget-friendly version with stock intake runners (and ported exhaust) that it claims is good for 20 to 35 rwhp. The pricier 267-cc head is known for its torque and throttle response. Flow (cfm) increases 43.2 on the intake side and 15.5 on the exhaust while still using factory valves (note base-line flow numbers are considerably lower than the prior stock heads). Flow continues to rise at .700-inch lift making these a great pairing with a large camshaft. The only requirement for installing these heads is a 4-inch-or-larger bore. $995 covers the machining and labor cost for AI’s 267-cc program, with additional charges for upgraded valvesprings, retainers, valveguides, etc.
Advanced Induction
LS3, 275 cc
Three different sizes are offered in AI’s “821” casting, starting at 270 cc and then going up to 280 cc. The largest of the three is recommended for high-RPM and large-displacement applications, and the smallest works well in the 600- to 700-hp combinations that stay below 7,000 rpm. The 275-cc version, though, splits the difference and offers substantial port cleanup. AI says significant core shift among the GM castings causes large area to remain as cast, which does not affect function. The largest of the three CNC programs eliminates most of these areas. No special parts are required for installation. AI charges $995 for machining and labor, plus additional amounts for various valvespring and other upgrades.
Advanced Induction
LS7, 280 cc
The 280-cc LS7 heads represent the baddest of the factory castings, but only scratch the surface of AI’s capabilities. While subject to the same inconsistency of any factory head, a superior port design and finish make these a very attractive option for larger-cube builds whether road racing, daily driving, or drag racing. These heads have proven to be capable of 680 rwhp in a naturally aspirated, hydraulic roller, street engine. At .700-inch lift the raised intake runners peak at a staggering 391.7 cfm. As you’d expect from a factory casting, no extra requirements are needed for installation, just a 4.125-inch-or-larger bore. Machining and labor cost $1,195, additional charges apply for bronze valveguides, Manley exhaust valves, AI custom DLC-coated titanium intake valves, and various valvespring options.
All Pro/West Coast Cylinder Heads
LS7
Designed as a direct replacement for the factory LS7 head, the All Pro headuses stock rocker arms and intake manifold. However, with the West Coast’s two programs, neither is recommended. The smaller 267-cc intake flows 395 cfm at .650-inch lift; meanwhile, the larger 277-cc version exceeds 400 cfm at higher lift numbers. Both require a 4.125-inch-or-larger bore, and the 277-cc is intended for 440-plus-ci. Plenty of clearance for 7/16-inch-diame-ter pushrods is provided. As you’d expect from an aftermarket casting with this much potential, prices start at $3,300 (bare). Stainless-steel valves are a mere $288, and valvesprings for a hydraulic roller are $515. Titanium and inconel valves, solid-roller valvesprings, and Jesel shaft-mount rockers are available. (Photos Courtesy West Coast Cylinder Heads)
Arao Engineering
LS7 Stage II, 32-Valve
The Arao (pronounced “arrow”) LS7 heads boast some of the best exhaust numbers in the business making them ideal for forced induction. The revolutionary 32-valve head uses a unique rocker system that uses pushrods to activate four valves per cylinder and make better use of the chamber. These heads are perhaps the most exotic and least tested; however, the potential is obvious when you consider how much power 32-valve Ferrari V-8 engines make per cubic inch. Arao says the dual intake valves are equivalent to a 3.3-inch intake valve, and the exhaust valves equal a single 2.8-inch valve in terms of curtain flow area. The chamber is a fast-burn, low-detonation design that requires less spark advance at peak power levels. These heads are compatible with standard LS pistons and camshafts, though Arao says less lift is needed due to the high flow “under the curve.” A cathedral port version is also near production. These revolutionary heads command a hefty price, commensurate with the tremendous R&D required. Prices start at $7,499, and the heads come fully assembled with valve covers and rocker system (required for installation). Custom pistons are recommended for high-compression engines that need valve reliefs for adequate piston-to-valve clearance. (Photos Courtesy Arao Engineering)
Brodix
STS BR 7 273
Brodix is no stranger to building high-quality cylinder heads (dating back to the 1970s), but the company is a newcomer to the LS market. These LS7-style heads make up its first offering, boasting excellent flow numbers for the runner size thanks to the straight runners with excellent line of sight. The largest CNC version uses huge valves to achieve more than 416 cfm at .700-inch lift. A smaller (264 cc) CNC version is also available for lower-lift cam, street applications that flow 376 cfm at .650-inch lift, and an un-ported version that hits 364 cfm. All heads are made of A-356 virgin alloy, use the standard 12-degree valve angle, and are compatible with LS7 components such as intake manifolds, rocker arms, and exhaust manifolds (or headers).
Lingenfelter Performance Engineering
Includes:
LS3, CNC
LS9, CNC
LS7, CNC
John Lingenfelter was not only a racing legend, but he spent more than 30 years reinventing cars and trucks for world-class performance. Today that tradition is carried on by current owner Ken Lingenfelter and a talented crew of builders and engineers. Extensive research and development has been poured into the LS market, as LPE’s sole concern outside of servicing its past small-block LT5 and LT1 customers. LPE has programs for stock and aftermarket castings as well as custom porting and a variety of other services (such as engine building) and products for the street, drag race, road race, and top-speed crowd. (Photos Courtesy Lingenfelter Performance Engineering)
CNC LS3
CNC LS9
CNC LS7
Lingenfelter Performance Engineering
LS3, CNC
Lingenfelter Performance Engineering (LPE) is one of the oldest and most prestigious names in the LS industry. Countless hours have been spent developing the program for LS3 heads, which is carried out on an in-house 5-axis CNC machine. These heads are clearly built with its supercharged and turbocharged customers in mind, using Inconel exhaust valves to handle the added heat while also keeping valvetrain weight to a minimum. These were engineered with more street-based engines in mind as flow tapers off after .650-inch lift where it hits 352 cfm. These heads are available for 10:1 or 11:1 compression (with stock bottom-end LS3s). As with all L92 heads, a 4-inch or larger bore is required. Fully assembled with Comp Cams 918 springs and titanium retainers these heads cost only $1,098.
Lingenfelter Performance Engineering
LS9, CNC
LPE’s LS9 heads are very affordable, yet high-flowing with a light-weight valvetrain. It is a combination that would suit naturally aspirated or forced-induction applications; however, the stronger alloy, thicker deck surface, and better clamping capabilities make them best suited for boost or juice. Like all LPE heads, these were created by sectioning a stock head to measure wall thickness and then countless hours of hand porting were spent before recreating on the 5-axis in-house CNC machine. LPE’s LS9 program is virtually identical to that of the LS3, L92, and LSA, as it does away with the “wings” as they impede flow and are believed to cause ignition timing restrictions (that would otherwise cost you power). These heads require a 4-inch- or-larger bore and ARP head studs, but are machined to except an LS3 or L92 intake manifold. LPE’s LS9 heads cost $1,489 fully assembled with factory titanium intake valves and sodium-filled exhaust valves, Comp Cams 918 springs, and titanium retainers and locks.
Lingenfelter Performance Engineering
LS7, CNC
Despite the heads coming from the factory with a clean CNC porting, there is plenty of room for improvement, as LPE proves with its LS7 program. These heads hit a whopping 395 cfm before falling off at .700-inch lift. LPE uses these heads in its 630- and 660-hp C6 Z06 packages, where maintaining velocity, torque, and street manners is very important. The same program is also offered on Chevrolet Performance’s six-bolt version of the LS7 head for those utilizing the extra clamping of an aftermarket block. With a supplied core, prices start at $1,095 depending on valvespring options; the LSX casting starts at $3,595 (no core required).
Livernois Motorsports
Includes:
L92 Stage 3, CNC
LS7, CNC
Livernois was the first to produce aluminum radiators for automotive use as well as the tooling and machines to produce them. Livernois offers CNC programs for OEM and aftermarket castings. In the LS community, Livernois is widely known for its fifth-generation Camaro products and services, and has managed to produce the very first 2012 Camaro ZL1 to run a 9-sec-ond quarter-mile—using a Livernois cam and CNC-ported heads. (Photos Courtesy Livernois Motorsports)
CNC Stage 3 L92
CNC LS7
Livernois Motorsports
L92 Stage 3, CNC
This Michigan-based engine builder and tuner churns out plenty of potent LS3 Corvettes and 2010 Camaros, so it’s no surprise it has several cylinder head packages. Livernois’ Stage 3 uses Manley stainless-steel valves with the boost addict in mind, and its own proprietary dual-coil valvesprings and titanium retainers. A Stage 2 package is also available using stock GM valves, using the same carefully shaped port design that is crafted on a 5-axis CNC machine. Flow numbers hit 359.9 cfm at .800-inch lift. No core is required with the $2,099 price tag. As with all L92/LS3 heads, the minimum bore needed is 4.00 inches.
Livernois Motorsports
LS7, CNC
Livernois’ program for the OEM LS7 casting or GMPP LSX-LS7 (6-bolt) casting boasts equally impressive flow numbers. Suitable for large-bore street cars; up to 388.5 cfm can support plenty of horsepower whether naturally aspirated or forced induction. Using a Livernois cam and LS7 bottom end, these heads typically make more than 615 rwhp with supporting components (air intake, headers, exhaust, etc.) on a Corvette Z06. Naturally, a 4.125-inch bore is required. With a customer-supplied core, the parts and labor cost $1,430. The 6-bolt, LSX-LS7 Stage 2 heads cost $3,800 (fully assembled). A Stage 3 version is also available, which adds $400 to the price.
Mast Motorsports
Includes:
LS3, 11-Degree Small Bore
LS3, 11-Degree Medium Bore
LS3, 11-Degree Large Bore
LS7, 12-Degree, 305 cc
The fast-growing Mast Motors-ports was founded on the principles of engineering, developing high-quality LS components, and thorough assembly of LS crate engines—embracing new and cutting-edge technology. Mast is constantly developing new products for the LS market that push the design envelope for the highest performance.
LS3 11-Degree Small Bore
LS3 11-Degree Medium Bore
LS3 11-Degree Large Bore
LS7 305-cc 12-Degree
Mast Motorsports
LS3, 11-Degree Small-Bore
Mast brought the first small-bore rectangular port heads to market a few years ago, and since then there still has not been a higher flowing head for a 3.90-inch bore (up to 353 cfm). An 11-degree valve angle enables the straight runners as well as plenty of piston-to-valve clearance with big cams. The large CNC-ported runners make these heads best suited for high RPM or forced induction. The clean-sheet casting design uses a .750-inch-thick deck, and is compatible with all LS3/L92 valvetrain components (including stock rocker arms) and intake manifolds. These heads retail for $1,300 each, fully assembled.
Mast Motorsports
LS3, 11-Degree Medium-Bore
The added material, altered port shape, and valve angle of Mast’s casting enable some incredible flow capabilities over the factory heads. Flow continues to rise to .700-inch lift, where it hits 372 cfm, making it a good match to a high-lift cam. Stroker and boosted engines can benefit the most from the added flow (cfm); however, the small (compared to stock) runners keep velocity high enough to make good power with stock cubic-inch, naturally aspirated combos with a 4.00- to 4.070-inch bore. If you are using aftermarket blocks you can go with the 6-bolt version to accommodate the extra head bolts. Like the small-bore head, retail price is $1,300 each.
Mast Motorsports
LS3, 11-Degree Large-Bore
Though the runners are not much larger than the medium-bore version, the huge LS7-size valves make all the difference. The flow numbers rival any ported LS7 head as a result, yet it is still compatible with LS3 valvetrain components and intake manifolds. Flow numbers hit an amazing 390 cfm at .700-inch lift, unheard of for an LS3-style port. Six-head-bolt provisions come standard to match aftermarket blocks and provide extra clamping force. Like the other rectangular port heads from Mast, these also boast an 11-degree valve angle and .750-inch deck from their clean-sheet casting design. A 4.125-inch bore is required, as are LS7-style rocker arms (OEM or aftermarket). Retail price is $1,600 each.
Mast Motorsports
LS7, 12-Degree, 305 cc
Mast also has its own twist on the LS7 head, starting with a higher-flowing version of the original with a more conservative 274-cc intake runner. However, the big bad boy 305-cc is the one racers and 454- to 502-ci stroker builders gravitate toward. This head continues to flow as the flow bench hits 1.00-inch of valve lift and 410 cfm. The large runners are not for the faint of heart, small cams, or average street cars. Six-head-bolt provisions are standard. These heads are compatible with LS7 rockers and other components, and a 4.125-inch (or larger) bore is required. Each head costs $1,600.
Procomp Electronics LS3
Another clean-sheet casting comes from Procomp, which uses high-grade aluminum and superior quality control to outdo the factory casting. The advanced port design easily surpasses some of the finest CNC factory heads, and also utilizes a proprietary multi-angle seat design. This head comes fully CNC-machined either bare or fully assembled with stainless valves and dual valvesprings. A 4.00-inch-or-larger bore is needed with stock-size valves; however, upgrades are available for large-bore applications. Retail price is $645 each for a bare head. (Photos Courtesy Procomp Electronics)
Scoggin-Dickey Parts Center
LS3, CNC
Scoggin-Dickey Parts Center, the largest GM Performance Parts dealer, has a program of its own for LS3 heads that is definitely worth a look. The price is what makes these heads so attractive. Throw in some great flow numbers, and naturally aspirated builds can support plenty of power. As with any LS3/L92 head, a 4-inch-or-larger bore is required (with no other special considerations). For a pair of assembled heads, Scoggin-Dickey offers the CNC LS3s for $750 (that is not a typo). (Photos Courtesy Scoggin-Dickey)
Texas Speed/Precision Race Components
Includes:
LS3/L92, CNC
LS3, 250 cc
LS7, CNC
LS7, 285 cc
PRC offers its own aftermarket casting. The company is known for extensive flow and dyno testing of all its heads as well as affordability. PRC is hard to beat in terms of quality and performance per dollar. PRC cylinder heads have several long-standing records in the LS drag race community. (Photos Courtesy Texas Speed)
CNC LS3/L92 and 250-cc LS3
CNC LS7 and 285-cc LS7
Texas Speed/Precision Race Components
LS3/L92, CNC
PRC was one of the first to jump on the L92 bandwagon, developing a CNC program to take the GM casting to the next level at a very comfortable price. The flow numbers speak for themselves; however, it is worth noting how extensively these heads have been dynotested prior to their release. Many different options are available, from the GM L92 valves to the lighter hollow-stem LS3 valves and aftermarket stainless-steel variations on both. Two different valvespring options allow up to .675-inch-lift cams, and these heads can also be purchased without springs. A 4.00-inch bore is required. Prices start at $900 with a customer-supplied core, or $1,330 (outright).
Texas Speed/Precision Race Components
LS3, 250 cc
PRC’s own casting of the LS3 head utilizes a 13-degree valve angle and revised runner shape to make a similar flowing intake runner with much less volume (and much more velocity). Meanwhile, the exhaust runner, which is very restrictive on the stock casting, is uncorked considerably. This head was designed with stock cubic-inch builds in mind; however, their flow capabilities also make them a good match for strokers. The rolled valve angle allows greater piston-to-valve clearance (.040 inch) for higher compression and larger cam-shafts. Available valvesprings handle either .675- or .700-inch lift, where this head peaks in flow (361 cfm). A 4.00-inch-or-larger bore is required. Retail price is $2,200 fully assembled.
Texas Speed/Precision Race Components
LS7, CNC
PRC improves upon the factory CNC porting by up to 40 cfm, allowing the intake to reach 393 cfm at .700-inch lift while still keeping the intake runner at a fairly conservative 270 cc (perfect for street cars). The high-flowing exhaust runner also makes this head a good choice for boost or nitrous, especially if you check the box for six head bolts (and PRC’s own casting), which is a cheap upgrade. Choose from three different valve options, starting with the basic stainless-steel to hollow-stem and titanium (like stock). Several different valvesprings are available as well, for up to .700-inch-lift cams. An LS7-size bore or larger is required. The stock castings cost $2,000 (with no valvesprings) and the 6-bolt version adds only $400.
Texas Speed/Precision Race Components
LS7, 285 cc
PRC’s highest-flowing head provides enough airflow for very extreme applications, hitting a magic 407 cfm at .700-inch lift. The aftermarket castings afford several advantages, such as the extra material to make a 285-cc intake runner, a thicker deck surface, and 6-bolt provisions for aftermarket blocks. The massive 2.250-inch intake valves are available in standard stainless steel; however, the sheer weight limits cams to just .616-inch lift. With this type of flow, a higher-lift cam and the lighter hollow-stem or titanium valves are recommended. A 4.125-inch-or-larger bore is required. The 285-cc LS7s start at a reasonable $2,400.
VMAX Motorsports
LS3, CNC
VMAX has made its name porting top-end components such as throttle bodies, intake manifolds, and cylinder heads for the LS market. So it should come as no surprise that the company put together an impressive CNC program for the L92/LS3 head. Using either stock or REV valves, VMAX has a very cost-effective package with a good combination of flow and velocity. Each head is ported with a 5-axis CNC machine and then flow tested, resurfaced, and assembled in-house with the customer’s choice of components. The heads can be flat-milled to .040 (maximum) inch, or angle-milled to the high 50s or low 60s. A 4-inch bore is required, with no other special requirements. These heads go for $1,950, plus an additional $240 charge for angle milling.
Wegner Motorsports
LS3/L92, CNC
NASCAR fans may be familiar with Wegner, but for the uninitiated this Wisconsin-based builder started in the 1970s in a backyard shed building hot rods. As the demand for Wegner engines grew, so did the customer base and facilities to satisfy them. Eventually, the reputation grew, and Wegner engines found their way into every division of NAS-CAR. Wegner-spec LS engines can be seen in racing classes throughout the country, which led to several products including these CNC-ported heads. With this sort of background, durability is a concern, which is why Wegner ensures that there is plenty of material beneath the spring pockets where ported LS3 heads can break through using heavier valvesprings. The valveguides are honed for proper clearance, and the deck is resurfaced (chamber size varies as needed). Wegner also ports LSA and LS9 heads with very similar flow, which peaks at .700-inch lift with 360.5 cfm. All heads require a 4.00-inch bore or larger. Retail price is $1,650.
West Coast Cylinder Heads
L92 Stage 2, CNC
WCCH designed this CNC program for the L92 casting for larger-cubic-inch combinations such as 408 and 427 strokers; however, these heads have also proven to be a good source of power on stock-cube, naturally aspirated LS3s. Higher-lift cams can take advantage of up to 363.6 cfm (at .700-inch lift). A Stage 3 is also available, which is designed for even larger-cube engines and uses 2.20-inch intake valves to flow 380.1 cfm at .700-inch lift. Base price for the Stage 2 is $2,045 with Patriot Gold valvesprings. Like any L92/LS3, there is a 4.00-inch bore minimum.
World Products
LS7 Warhawk
While also available as-cast (285 cc), which flows 333 cfm, the CNC-ported version delivers the finished product for racers who can utilize the 403 cfm at .800-inch lift. This casting is ideal for high boost or nitrous in particular because of the stronger 355-T6 alloy, raised valve cover rails for aftermarket rocker clearance, and hardened valve seats. These large-runner heads have a 12-degree valve angle, like stock, and are compatible with factory LS7 rocker arms and stands. The heads can accommodate 1.625-inch-diameter springs, and several are available. A 4.125-inch-or-larger bore is required. Base price is $1,130 each, fully assembled, through Summit Racing. (Photos Courtesy World Products)
Written by Dave Grasso and Posted with Permission of CarTechBooks
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