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  • LS3 Cylinder Head 88958758

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Item #: 88958758
Reg. Price: $859.89
Our Price: $756.72



GM Performance Parts’ (GMPP) has released a high-flow, CNC-ported version of the LS3 cylinder head. It flows more than 350 cfm at 0.600-inch lift (intake side) at 28 inches of water restriction – or nearly 10 percent more than the stock casting – to promote greater power across the rpm band and maximize the advantage of additional performance parts, such as a “larger” camshaft and high-flow intake manifold.

. CNC porting is a precision machining process that enlarges and optimizes the shape of the intake and exhaust ports to enhance airflow. And while a horsepower increase can be realized by installing only the heads, they are more effective when matched with complementing camshaft, valvetrain, intake and exhaust components.

“This new cylinder head is a great choice for builders looking to get the most out of a simple, bolt-on cam-and-heads swap on their new Camaro SS or Corvette,” said Dr. Jamie Meyer, product integration manager for GM Performance Parts. “It also complements a bolt-on supercharger by maximizing the airflow, particularly at higher rpm.”

GMPP engineers recommend the LS Hot Cam (part number 88958753) or the high-rpm “ASA” camshaft (part number 88958770) as suitable partners with a set of CNC-ported LS3 heads. The LS Hot Cam delivers 0.525-inch of lift and 219/228 degrees of duration on a 112-degree lobe separation angle. The hotter ASA cam matches the 0.525-inch lift, but delivers 226/236 degrees duration on a tighter 110-degree lobe separation angle. Both camshafts are compatible with the valve springs included with the cylinder head assemblies.

Designed for airflow

The CNC-ported LS3 head features 276cc intake runners and 92cc exhaust ports, along with a combustion chamber volume of about 68.5cc. That’s the same volume as stock LS3 heads, which maintains the stock compression ratio. It will fit any LS engine with cylinder bores of 4.000 inches or larger, including 6.2L L92 truck engines.

Each head is delivered fully assembled, with 2.165-inch hollow-stem intake valves and 1.59-inch solid-stem exhaust valves, as well as valve springs, valve locks, spring retainers and valve stem seals. The maximum recommended valve lift with the stock valvetrain components is 0.550-inch.

Below are the airflow specifications for the CNC-ported LS3 head, based on flowbench testing conducted with 28 inches of water restriction.

•Over 10 percent more flow than the stock cylinder head
•Simple bolt on performance component
•Compliments a bolt-on supercharger
•Fits any LS engine with a bore of 4.0 inches

Heads 12629063 and 88958758 are assembled with the following components:
12569427 Intake Valves
10166344 Valve Spring Retainers
12582719 Exhaust Valves
12482063 Intake Valve Stem Seals
12625033 Valve Springs
12482062 Exhaust Valve Stem Seals
10166345 Valve Locks 

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