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Greg@PacePerformance
08-16-2011, 08:26 AM
I have a pair in stock.
88958758 - $599.00 each complete (http://paceperformance.com/i-7139127-88958758-cnc-ls3-cylinder-head-assembly.html)
Give me a call at Pace since I can't touch this price.
-Greg



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: gmperformanceparts.com. 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 airflowThe 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

InfantryG8GT
08-16-2011, 08:30 AM
How are these in relations to the stock L92 heads on our GT's?

Greg@PacePerformance
08-16-2011, 08:41 AM
GM says the L92 head flows
Lift Intake Exhaust
.200 151 111
.300 208 152
.400 256 174
.500 294 183
.600 316 189

And the LS3 head comes with the lighter hollow intake valves.
The new CNC head flows a little better on the intake side but worlds better on the exhaust side.

Devilish34
08-16-2011, 08:47 AM
I'm broke :(

Greg@PacePerformance
08-16-2011, 08:51 AM
Boo on you :)
Would cost you a little more as well since you would have to change the intake also.

InfantryG8GT
08-16-2011, 09:25 AM
The L76 Intake WILL NOT....work on these?

Greg@PacePerformance
08-16-2011, 09:27 AM
Yes the L76 intake will work, but Devilish has a '07 Corvette now with the LS2

Devilish34
08-16-2011, 09:29 AM
L76/LS3 will work.... I dont have a L76 anymore I have a LS2

-Ray-
08-16-2011, 05:40 PM
I talked to a GM guy today telling me about those heads. Much better than the expensive shop heads.

Greg@PacePerformance
08-16-2011, 06:05 PM
I can save you shipping Ray and bring them to the G8 meet ;)

Devilish34
08-16-2011, 06:24 PM
I can save you shipping Ray and bring them to the G8 meet ;)

Talk Ray into buying my nitrous and drag pack and I just might buy them

-Ray-
08-24-2011, 02:58 PM
I can save you shipping Ray and bring them to the G8 meet ;)

I already have a set of Land speed heads on my G8. Thanks for thinking of me though. I do need an oil change kit now though.