CNC-Ported LS3 Cylinder Head Offered by GM Performance Parts

Do you want increased airflow for your LS engine? Look no further than GM Performance Parts and their new high-flow, CNC-Ported LS3 Cylinder Head. Not only will this head increase the flow of your LS3 engine, it can also be used on any LS engine bored to 4.0 inches.

Official Release:

GM Performance Parts Announces High-Flow, CNC-Ported LS3 Cylinder Head

GRAND BLANC, Mich. – 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.

The new head carries part number 88958758 and an MSRP of $700. It is available now through GMPP dealers and retailers, including through the GM Performance Parts Web site: 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.
LIFT (mm)        LIFT (inch)        CFM – INTAKE        CFM – EXHAUST
1.0                0.039                  27.612                  21.037
2.0                0.079                  60.714                  44.679
3.0                0.118                  87.300                  75.053
4.0                0.157                124.341                103.872
5.0                0.197                161.414                127.083
6.0                0.236                195.628                147.451
7.0                0.276                223.566                167.097
8.0                0.315                251.641                186.501
9.0                0.354                275.218                206.322
10.0                0.394                294.406                222.840
11.0                0.433                311.917                234.353
12.0                0.472                327.475                242.617
13.0                0.512                340.917                247.045
14.0                0.551                348.538                249.514
15.0                0.591                351.323                252.371
16.0                0.630                359.135                255.246
17.0                0.669                365.137                257.451
18.0                0.709                361.738                259.690
19.0                0.748                364.504                260.962
20.0                0.787                369.196                262.666


  • 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

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About the author

Lindsey Fisher

Lindsey is a freelance writer and lover of anything with a rumble. Hot rods, muscle cars, motorcycles - she's owned and driven it all. When she's not busy writing about them, she's out in her garage wrenching away. Who doesn't love a tech-savy gal that knows her way around a garage?
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