LS7, LS3, and LS9 Cylinder Heads
Earlier Gen III LS heads, such as those found on LS1, LS6, and various Q Series truck engines, feature tall intake ports referred to as “cathedral” ports. The cathedral-roof shape at the top accommodates the fuel-injector path. The LS2 engine also features cathedral-port heads but is technically considered a Gen IV engine due to the change in cam sensor location. We’ll limit our discussion to Gen IV heads with rectangular intake ports.
In the Gen IV versions of this later generation of LS engines, we’re dealing with two separate cylinder head castings. The LS3, LS9, and L92 all use essentially the same cylinder head foundation, featuring a four-digit identification number, which is at the top of the head just outside the valve cover rail. The casting number for the LS3 head is 0821. The LS9 head features no such casting number; rather, the designation “LS9” is lightly engraved on the lower left of the exhaust side of the head. The LS7 cylinder head is unique, with identification number 8452.
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Gen IV “rectangular”-port cylinder heads include the LS7, LS3, L92, and LS9 variants. Basic differences include intake port dimensions, rocker arm mounting pedestals, and combustion chamber volumes.
All Gen III heads feature tall and narrow cathedral intake ports. This includes LS1, LS6, and LQ truck variants. The LS2 also features cathedral-port heads, although it’s considered a Gen IV engine primarily because the cam timing sensor was moved from the rear of the block to the front timing cover. The cathedral-port design is generally noted for better low-end torque, while the Gen IV rectangular ports are generally known for superior midrange and top-end performance. Cathedral ports measure about 1 inch in width and about 3.125 inches in overall height.
The LS3, LS9, and L92 heads are “as-cast” heads, with intake and exhaust ports and combustion chambers shaped during the precision casting process. The LS7 cylinder head features intake and exhaust ports and combustion chambers with a more refined dimensional and surface finish that is CNC-machined.
Intake port dimensions also vary between the LS3, LS9, and L92 and the LS7 head versions. The intake ports on the head used for the LS3, LS9, and L92 are 1.250 inches wide x 2.550 inches tall, while the intake ports on the LS7 head are 1.350 inches wide x 2.40 inches tall.
The LS7 cylinder head was offered in 2007–2009 Corvette Z06 models. Identifying an LS7 head versus the LS3, LS9, and L92 heads is fairly easy. The LS3, LS9, and L92 heads feature flat rocker pedestals (to accept separate rocker arm rails), and the ports and chambers feature a cast finish. The LS7 head features individual rocker arm radiused stands and all ports and chambers display a machined surface.
From left to right: LS7, LS3, and LS9 cylinder heads. Notice the taller intake ports on the LS3 and LS9 heads.
Shown here is a cutaway view of an L92 head. The intake port runner design differs slightly among the various head versions, but all are very similar in shape.
The LS3 cylinder head has become very popular, in part because of the improved flow of the Gen IV rectangular-port design and its relatively attractive street price. General Motors made a lot of LS3 engines along with its truck counterpart, the L92, and as a result these heads are available in great numbers in salvage yards. Even brand-new head prices have become very reasonable; hence their popularity.
Shown left to right: LS7, LS3, and LS9 heads. Combustion chamber volumes differ among the three variants. The LS7, L92, and LS9 feature 70-cc chambers, while the LS3 has 68.4-cc chambers.
Note that while stock cylinder heads feature a four-boltper-cylinder-head bolt layout, GM LSX versions are offered with a six-bolt-per-cylinder layout. Aftermarket heads are also available in four- or six-bolt versions.
LS7
LS7 cylinder heads feature a larger combustion chamber and wider valve layout. Because of this, LS7 heads cannot be installed onto blocks that feature a cylinder bore size of under 4.100 inches, as valves may contact the top edges of the cylinder bores. LS7 heads may only be installed onto blocks that feature a 4.100-inch or larger cylinder bore diameter. Unlikeother factory LS heads, LS7 factory heads are fully CNC-machined at the combustion chambers and ports. Beneficial porting work may involve only port matching the intake ports and/or the intake manifold ports to remove any potential flow obstructions. Due to the LS7 unique intake manifold deck, only intake manifolds designed for the LS7 heads may be utilized due to port match and manifold bolt pattern.
LS7 heads are casting number 8452 and feature slightly raised ports, altered valve angle, and larger titanium intake valves. Exhaust valves are sodium filled and have been known to cause failures. A popular remedy is a change to stainless-steel exhaust valves. Approximate flow bench results at .600-inch lift are about 370-cfm intake and about 240-cfm exhaust.
LS7 intake port deck view. Note the shorter intake port height compared to LS3, LS9, and L92.
The LS7 heads feature fully CNC-machined combustion chambers with 70 cc of volume.
LS3
The LS3 factory head features lightweight hollow steel intake and solid-stem exhaust valves. In stock form, flow bench results have shown flow rates of 296 cfm intake and 208 cfm exhaust, at full valve lift of about .600-plus. This head is intended for blocks that feature a minimum cylinder bore diameter of 4.00 inches.
The LS3 cylinder head has 260-cc intake runners and 92-cc exhaust ports. In addition, it has a combustion chamber volume of about 68.4 cc. These heads fit any LS engine with cylinder bores of 4.000 inches or larger. It also features 2.165-inch hollow-stem intake valves and 1.59-inch solid-stem exhaust valves.
Shown here is an LS3 combustion chamber with 68.4 cc of volume. All factory production LS heads feature an as-cast combustion chamber except for the LS7, which has CNC-machined chambers.
L92
L92 heads are essentially the same casting as the LS3 heads. The difference is the weight of the intake valves: L92 heads feature solid valves and the LS3 has lighter, hollow-stem valves. L92 and LS3 heads flow pretty well in stock form, but they can benefit from porting by opening up the throats a bit and reducing the big rocker bolt bosses in the runners and massaging the exhaust ports. This is best done on CNC for more precise and repeatable results. CNC porting also requires much less time as opposed to hand porting. Performing a good valve job is more critical, making sure that the seats are concentric and that the valves are sunk into the seat at the same depth.
The L92 combustion chamber features 70 cc of volume.
LS9
The factory LS9 cylinder head was designed for higher dynamic compression to suit a supercharger application. This head features a stronger, more-dense alloy along with beefier webbing reinforcements, again to better handle forced induction pressures. Like the LS7 head, the LS9 features a lightweight titanium intake and hollow sodium-filled exhaust valves. To promote air/fuel mixture efficiency, a “swirl wing” is designed into the intake valve boss at the base of each intake runner. The valve guide boss casting features a pronounced vertical riser, or “wing,” that promotes a swirl effect before the air/fuel charge reaches the valve. In stock form, full-lift flow has been documented at 270 cfm at the intake and 201 cfm at the exhaust ports. CNC port machining that removes the swirl wing has been reported to increase flow to 322 cfm intake and 218 cfm exhaust.
The LS9 CNC-ported cylinder heads have enhanced webbing and a stronger deck for greater rigidity and minimal distortion. The A356T6 alloy also withstands higher-performance service, and in stock trim it is supercharged.
LS9 cylinder head castings are factory etched with an “LS9” designation on the lower left of the exhaust side, under the spark plug port.
The LS3, LS9, and L92 all use essentially the same cylinder head foundation, featuring the four-digit identification number (top of head just outside the valve cover rail) 5364. The LS7 cylinder head is unique, with identification number 8452.
The LS9 and L92 heads feature flat rocker pedestals (to accept separate rocker arm rails). The ports and chambers feature a cast finish. TheLS7 head features individual rocker arm radiused stands and all ports and chambers display a machined surface.
All factory LS heads, including Gen III and Gen IV, are equipped with tapered, or “beehive,” valve springs instead of traditional parallel-wound springs. The beehive spring design, which features an oval wire instead of a round wire, features progressively smaller coils from bottom to top. This was intended to reduce retainer mass and diminish valve spring harmonics/frequencies. However, opinions among performance engine builders vary, opting to choose either beehiveor parallel-wound-style springs. Installed height on LS7 heads is 1.960 inches with 310 pounds at 1.370 inches open pressure. LS3 and LS9 springs feature an installed height of 1.800 inches and 1.250 inches at 295 pounds.
In addition, the LS3, LS9, and L92 heads are originally equipped with the tapered “beehive” valve springs, while the LS7 head features “straight” valve springs without the beehive taper.
An LS9 combustion chamber with 70 cc of combustion chamber volume. The heads come with production lightweight titanium intake valves and sodium-filled exhaust valves.
LS9 cylinder head, deck view. The heads are rotocast from strong A356T6 aluminum alloy, so the molten alloy is equally distributed in the mold for greater density and strength.
Unlike the LS1, LS6, and LS2 heads that feature the tall, skinny cathedral intake ports, the LS3, LS9, L92, and LS7 heads feature a conventional rectangular-shaped intake port. Intake port dimensions also vary between the two head versions. The intake ports on the head used for the LS3, LS9, and L92 are 1.250 inches wide x 2.550 inches tall, while the intake ports on the LS7 head are 1.35 inches wide x 2.40 inches tall.
Cylinder Head Interchangeability
When mixing and matching heads and blocks, the rule of thumb is that you cannot use a cylinder head that features a valve layout that is too large for the bore diameter in the block. For instance, you cannot run an LS7, LS3, or LS9 head on a Gen III block because the valves will contact the edges of the bores. The LS7 head requires the use of 4.100-inch-or-larger bores; theLS3 and LS9 heads require 4.000-inch bores or larger. An exception is the LS2 block, which will accept LS3 or LS9 heads.
While all production-based LS heads and blocks feature a four-bolt design, dedicated performance blocks and heads feature a six-bolt design, where an additional head bolt is added at the inboard and outboard locations, inline with the bore centerline. The added two bolts per cylinder provide extra strength for high cylinder pressures. Blocks that feature this six-bolt design include GM’s LSX block, as well as offerings from various performance aftermarket makers, such as Dart.
You need to pay attention to the block’s bore diameter. Running a cylinder head intended for a larger bore size can result in valves crashing into the block. For instance, you cannot install an LS3, LS9, or LS7 head on an LS1, LS6, or LS2 block (at least not without some creative deck/bore notching to clear the valves).
- LS1 and LS6 blocks will accept only LS1, LS6, and LS2 heads.
- LS2 blocks can use LS1, LS6, or LS2 heads, as well as L92-style heads, which include LS3 and LS9 heads.
- LS3 and LS9 blocks can use LS1, LS6, LS2, LS3, or LS9 heads.
- The LS7 blocks can accept any LS head.
All production LS blocks except the LS3 and LS9 feature a 4-bolt-per-cylinder head bolt layout, for a total of 10 head bolts per head. All these heads use 11-mm x 2.0 thread except the LS9, which features 12-mm x 1.75 thread. However, the GM LSX race block, LS3, and LS9, along with a host of aftermarket race blocks, feature a 6-bolt design, with 18 bolts total per head. Two additional bolts per cylinder, one inboard and one outboard of the bore centerline, are added. This provides added head securing and rigidity for high-cylinder-pressure applications.
Regarding head-to-block swaps, the four-bolt heads or the six-bolt heads can be installed on either four-bolt or six-bolt blocks. Installing a four-bolt head to a six-bolt block simply won’t provide the added cylinder head clamping available with the six-bolt head. Also, while a six-bolt head can be installed to a production four-bolt block, you simply won’t be taking advantage of the added bolt locations offered by six-bolt heads. Appearance-wise, the outboard four-bolt bosses simply hang over the block deck but won’t cause an issue. If a six-bolt head is installed on a four-bolt block and you don’t like the looks of the extra bosses on the exhaust side of the heads, these bosses can be milled off, but this is not necessary.
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Shown here is an example of a six-bolt head, from Trick Flow. Aftermarket head makers offer LS heads in both four-bolt and six-bolt designs. Six-bolt block and head combinations require a special head bolt or head stud kit and head gasket designed for the six-bolt platform.
A six-bolt head can be mounted to a factory four-bolt block, even though you would not be taking full advantage of the head’s six-bolt design. The outer bolt bosses would simply hang out past the block deck. If this is the case, the extra outboard bosses may be milled off if so desired. This would occur only if you happened to get a good deal on a pair of six-bolt heads that you wished to use on your factory block.
Water Temp Holes
All LS heads feature a 12-mm x 1.5 female-threaded hole on the left of the exhaust side, intended for a water temperature sender. The sender is traditionally mounted to the left-hand head, but don’t forget to plug the hole on the right-hand head. If you’re dealing with a new or used head, this plug will already be in place with any luck. If the plug is missing, you can handle this in one of two ways: purchase a GM plug PN 11610259 for about $5, or simply use a 12-mm x 1.5 bolt with a shank length of about 20 mm along with an aluminum or copper crush washer. If the heads have been reconditioned, this plug on the right head might have been accidentally lost or ignored. It’s easy to forget, so make sure to plug this unused water hole; otherwise you’ll have a coolant-squirting mess when you start the engine.
Each head features a 12-mm x 1.5 threaded hole on the left area of the exhaust side. These holes are open to the cooling. The water temperature sender installs to the left-side head.
An example of a water hole plug on the right-side cylinder head, using a common 12-mm x 1.5 bolt and crush washer.
Rocker Arm Pedestal Rails
Two different rocker arm pedestal rail versions are used. One rail is designed for use on the LS1, LS6, and LS2. The other is designed for the L92, LS3, L99, and LS9.
The rail for the LS1, LS6, and LS2 features the pedestals centered (height-wise) on the rail. Each edge of the rail’s length is straight. The rail for the L92, LS3, L99, and LS9 locates the pedestals a bit offset, with one side of each pedestal extended out (one edge of the rail features individual pedestal bulges, or radiuses, that protrude out from the edge).
Gen IV rocker arms for L92, LS3, and LS9 applications feature an offset intake rocker and a straight exhaust rocker, both with 1.7:1 ratio.
Cast-in rocker pedestals are integral to the LS7 heads. The radiused pockets allow rockers to be directly bolted to the heads without the need for a separate rocker mounting rail.
The rail for the LS1, LS6, and LS2 features each cylinder’s pair of pedestals located 1.901 inches on center from each other. The rail for the L92, LS3, L99, and LS9 features the pedestal centers located 2.227 inches apart (center of hole to center of hole). The part numbers on the rails are 12552203 for the LS1, LS6, and LS2 rails and 12600936 for the L92, LS3, L99, and LS9 rails. The LS7 cylinder heads feature individual radiused rocker stands as an integral aspect of the casting and do not require the use of a separate rocker arm mounting rail. Rockers bolt directly to the LS7 heads without the need for a separate rail.
As an example of a pair of performance aftermarket rockers for LS Gen IV applications that require offset intake rockers, this underside view shows the slight offset of the intake rocker (left) at both the pushrod cup and roller valve ends. The offset intake rockers are necessary because of the larger valve diameters used in Gen IV applications.
A comparison of the rocker pedestal design on the LS7 head (left) and LS2/LS3/L99/LS9 head versions. Note that the LS7 rocker pedestals are part of the casting, allowing the rocker arms to bolt onto the head with no need for a mounting rail. The other style features flat pedestals, onto which a separate rocker arm mounting rail is installed. The rail is sandwiched between the head and rockers.
Factory original Gen III and Gen IV heads feature separate rocker mounting rails that allow mounting OEM rockers except for LS7 heads, which do not require a mounting rail. Note that Gen III and Gen IV rails seen here at the bottom are different; the Gen IV rails feature a different rocker arm mount spacing.
This view shows the underside of the rocker rails. Gen III rails have about the same amount of material above and below the holes, while Gen IV rails feature protrusions with the bolt holes slightly offset from the center length.
Aftermarket Performance Heads
Stock LS cylinder heads provide superior breathing compared to Gen I small-block Chevy heads. Since the introduction of the LS engine, cylinder head architecture has improved, and the original cathedral intake port design has evolved to rectangular-port designs, with the LS3/L92 heads currently leading the pack in terms of performance attributes. Thanks to performance aftermarket manufacturers, even furtherhorsepower gains are to be had. In some cases, gains of roughly 100 hp over stock have been realized because of changes in runner design, valve angle, port height variations, precision CNC-machined chambers and ports, capabilities to accommodate larger/taller aftermarket rockers and springs, increased deck thickness for added rigidity, and more. When you want to extend the power, torque, and RPM envelope, upgrading to aftermarket heads is definitely a move to consider.
Several companies offer aftermarket performance LS heads, including examples from Trick Flow, Dart, Mast Motorsports, Air Flow Research (AFR), Edelbrock, Racing Head Service (RHS), Bill Mitchell Products (BMP), and World Products. A wide array of configurations is available, including those with cathedral-port intakes (Gen III and LS2) as well as those with rectangular-port intakes (LS3, LS7, and L92). Heads are available in bare form and fully assembled, and as-cast or CNC-machined. Choices also abound in terms of intake port volume, combustion chamber volume, and both four-bolt-per-cylinder and six-bolt-per-cylinder formats.
Selecting a Cylinder Head
With all the variations in LS cylinder head platforms, choosing the head that’s right for your build can seem daunting at first. The first two considerations involve the type of intake manifold port and the piston bore size of your block. There are three types of factory intake ports: cathedral, square port, and raised square port. The cathedral-port design was featured on Gen III engines LS1, LS6, and LS2, as well as Vortec 4.8L, 5.3L, LQ4, and LQ9 iron blocks. The squareport, which is actually a rectangular port, is featured on factory L92, LS3, L99, L76, LS9, and LY6 engines. The raised square port was found on LS7 and GM LSX engines.
All three port designs flow well and produce good power. The cathedral port offers decent torque and is slightly more streetable, with the square-port designs offering higher peak horsepower at higher RPM, more suited for competition use. For the street, cathedral or square is acceptable for moderate power builds. For optimum power at higher engine speed, the square port is preferred. Naturally, the intake manifold must feature the same type of port to match the head.
The piston bore size is a critical factor. The 3.89-inch bore found on LS1 and LS6 engines will accept only cylinder heads that were intended for LS1, LS6, or LS2 applications. Using heads designed for a larger bore size runs the very real risk of valves contacting the edges of the cylinder bore. LS2 and LQ9 blocks feature a 4.000-inch bore and accept heads designed for LS1, LS6, LQ9, L92, LS3, and LS9 engines.
Other considerations involved in selecting the best cylinder head for your application include the weight of the vehicle, camshaft, intake manifold, exhaust system, transmission, gear ratio, drive tire diameter, and intended use. Aftermarket cylinder head manufacturers offer all three port designs, but with a range of intake and exhaust port volumes beyond what the factory heads provide. It’s best to discuss your build with the head maker for help in choosing a head. For instance, steeper gearing and/or high camshaft lift will likely require larger port volumes.
Trick Flow’s GenX 255 head is designed for six-bolt-per-cylinder block applications. Note the “extra” outboard bolt bosses.
The GenX 255 head features rectangular intake ports, CNC-finished. Airflow tests with a bore size of 4.065 inches are impressive. At .400-inch lift, intake flow was rated at 294 cfm and exhaust flow at 215 cfm. At .600-inch lift, intake flow was 363 cfm, with exhaust flow at 252 cfm. At a whopping .700-inch lift, flow rose to 383 and 258 cfm respectively.
Trick Flow
Trick Flow’s line of LS heads offers a dizzying array of cylinder head configurations in LS1, LS6, and LS2 cathedral-port and Gen IV rectangular-port designs. Offerings include as-cast and CNC-machined versions, in both bare and fully assembled configurations in a wide range of intake port volumes.
One example is its GenX 255 head for LS3 applications, PN TFS-3261T003-C01.
Dart
Dart offers both LS1-based (cathedral-port intakes) and Gen IV LS3–compatible versions, as well as a dedicated racing head. Its LS1-, LS6-, and LS2-based designs include the Pro 1 15-degree head in three different versions: 205-, 225-, and 250-ccintake runners. The Gen IV Pro 1 LS3–style head offers 280-cc intake runners and a six-bolt-per-cylinder fastener layout. Targeted at serious drag race applications, the Gen IV LS3–compatible Race Series rectangular-port head features 10-degree valve angles and a whopping 280-cc intake runner volume. The competition-only heads are unique, featuring 10-degree canted valves, with intake and exhaust valve locations reversed, and huge oval-port 368-cc intake runners. Dart’s line is designed for bore sizes of 4.125 inches or larger and for six-bolt-per-cylinder blocks.
Dart begins its offerings with the Pro 1 205-cc or 225-cc LS1, LS6, and LS2 head, equipped with beehive springs and cathedral intake ports. (Photo Courtesy Dart)
Dart’s Gen IV LS3–style head is intended for 4.125-inch bores or larger and accommodates six-bolt-per-cylinder blocks. Valve angle is 10 degrees, with canted valves. Intake and exhaust valve locations are reversed. It features 368-cc intake runners with oval ports. This is a serious race-only drag head. (Photo Courtesy Dart)
The Pro 1 LS3 head features a six-bolt-per-cylinder format, with 280-cc intake runners and rectangular intake ports. (Photo Courtesy Dart)
Air Flow Research (AFR)
AFR’s Mongoose line includes both cathedral-port-design LS1 and rectangular-port-design LS3. All heads are 100-percent port and chamber CNC-machined and include titanium retainers. The Gen III LS1 line offers intake runner volumes of 210, 215, 230, and 245 cc. All feature 15-degree valves.
AFR’s LSX Mongoose line of cylinder heads offers a selection of cathedral-port LS1 and LS2 heads, including intake runner volumes of 210, 215, 230, and 245 cc. Pictured here is the 215-cc version. (Photo Courtesy AFR)
The LS3-style head features 12-degree valves and 260-cc intake runner volume. It has 69-cc combustion chambers with 2.165-inch intake valves and 1.600-inch exhaust valves, dual 1.270-inch valve springs rated at 155 pounds at the seat, 8-mm bronze valve guides, and ductile iron valve seats.
MAST Motorsports
Mast’s Black Label line of LS heads offers both cathedral-port and rectangular-port heads. All Black Label heads feature a deck thickness of .750 inch. Mast offers a wide range of configurations.
In the LS1 and LS2 cathedral-port family, the following are available:
- LS1/LS2 225 cc for 3.890+ bore
- LS1/LS2 245 cc for 4.000+ bore
- LS1/LS2 275 cc for 4.125+ bore
- LS1/LS2 295 cc for 4.125+ bore
In the LS3 style range, the following are available:
- LS3 240 cc for 3.890+ bore
- LS3 280 cc for 4.125+ bore
- LS3 LSA 255 cc for 4.000+ bore
In the LS7 style, offerings include the following:
- LS7 265 cc for 4.000+ bore
- LS7 285 cc for 4.125+ bore
- LS7 305 cc for 4.125+ bore
In addition to the cathedral- and rectangular-port versions, Mast also offers an “all-out” race-only cylinder head called the Str8jacket Head, in a medium format for bore sizes of 4.000 inches or larger and the large for bores of 4.125 and larger. Both versions feature 47-cc combustion chambers and inline 11-degree valve layout. The medium bore head is equipped with 2.250-inch intake valves and 1.570-inch exhaust valves. The large bore head uses 2.300-inch intake valves and 1.600-inch exhaust valves. Valve spring options are based on specific lift requirements. Valves are offered in either titanium/ titanium or titanium/solid stainlesssteel packages.
Edelbrock
Edelbrock offers cathedral port heads for LS1, LS6, and LS2 Gen III and IV applications and a Gen IV LS3–style head. The LS3 head is offered to fit stock LS blocks with a four-bolt-per-cylinder layout or LSX-style blocks with six bolts per cylinder. The LS1, LS6, and LS2 head is offered with an intake runner volume of 215 cc, while the LS3 head features 230 cc.
Racing Head Service (RHS)
RHS’s Pro Elite line of LS heads includes a hefty array of LS7-style versions, with one even applicable to small-bore LS1/LS2 blocks. Rather than featuring the traditional cathedral intake ports found on other LS1/ LS2 heads, the small-bore LS7 head features LS7-style rectangular intake ports, providing a power upgrade that allows earlier engines to take advantage of the PS7 head design. This small-bore head features 260-cc intake runners that are raised .220 inch for a straighter shot to the cylinder.
In addition to the small-bore version, seven versions of the LS7 larger-bore heads are available, all with 29-cc intake runner volume. Differences are chamber volumes, types of valves and springs, and applications for hydraulic or solid lifters.
All heads in the Pro Elite series feature a six-bolt pattern, which allows installation in either four-bolt or six-bolt blocks. Heads are available bare or fully assembled.
Bill Mitchell Products (BMP)
Bill Mitchell Products (BMP) offers a killer LS7X head featuring hardened seats; bronze valve guides; spring seats machined for 1.560-inch springs (can be machined for 1.625-inch); Manley stainless-steel valves; 2.250-inch intake valves and 1.625-inch exhaust valves; CNC porting; 12-degree valve angle; flat-machined rocker pedestals that accept T&D rocker system 2351; 285-cc or 296-cc rectangular-port intake runners; 106-cc or 112-cc exhaust runners; 64-cc combustion chambers as cast, or 74-cc CNC; and a valve cover rail raised .300 inch for added rocker clearance. The head features a six-bolt head bolt pattern, allowing installation to four- or six-bolt blocks.
BMP’s LS7X head is offered with either 285-cc or 296-cc intake runner volume, and with either as-cast 64-cc combustion chambers or CNC’d 74-cc chambers. The rocker rail pedestals feature radiused pockets to accept a T&D rocker system. (Photo Courtesy BMP)
Written by Mike Mavrigian and republished with permission of CarTech Inc
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