anybody running the gmpp ls6 heads?
12-16-2010, 06:37 AM
#22
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I ran them for about 5 years ran a best of 11.10's on motor and 10.40's @ 132 on N2O. This was a 383 and 4l60E combo. The castings are very thin in the throat area. The pass head developed a pin hole and leaked. It was hard to find the leak. They make ok power and the valves are very lite weight and strong. Put some good springs on them and you should be good to go. Oh they are milled alot , check you manifold port exit to the head inlet. My LS6 manifold fit good the Fast had some issues.
12-16-2010, 05:47 PM
#24
I ran them on my n/a setup. Made 460 with a 9" rear gear, steel DS, etc. I had a trex in the car. The heads did spec out to 59.8 cc when i had the machine shop check them.
With a TH350 and same drivetrain it still made 430 to the wheels.
With a TIGHT nitrous converter (only was about 3100 on the motor) it went 11.0 all day long@120-121.
LOVED those heads. I think i posted the flow numbers on mine years ago.
With a TH350 and same drivetrain it still made 430 to the wheels.
With a TIGHT nitrous converter (only was about 3100 on the motor) it went 11.0 all day long@120-121.
LOVED those heads. I think i posted the flow numbers on mine years ago.
12-17-2010, 01:42 PM
#28
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I bought the heads in 2005 from Pace Performance (GMPP dealer) they were a Pontiac dealership at the time.
I just found a 2006 Pace Performance catalog so I gave them a call. The dealership has obviously closed,but they are still doing GMPP sales. I asked the tech about the availability of the light weight valves. He did a check and the hollow intake valves are definitely discontinued,however the sodium filled exhaust valves are still available for purchase.
I just found a 2006 Pace Performance catalog so I gave them a call. The dealership has obviously closed,but they are still doing GMPP sales. I asked the tech about the availability of the light weight valves. He did a check and the hollow intake valves are definitely discontinued,however the sodium filled exhaust valves are still available for purchase.
Last edited by david vericker; 12-17-2010 at 02:06 PM. Reason: Some additional info
12-17-2010, 02:40 PM
#29
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I doubt that the larger valves would benefit you much at all from a performance stand point. The larger valves may improve your cfm (flow rate) to a slight degree,however on the other hand your adding additional weight to the valvetrain by eliminating the light weight hollow and sodium OEM valves. Additional weight decreases the valvetrain stability at higher rpm's and slows the engines ability to rev at quicker pace. There could also be a shrouding affect with the larger valves in the LS6 heads and your block. I don't think the valve swap is worth the cost...just my two cent.
12-18-2010, 05:39 PM
#32
What kind of dyno numbers do you guys think I should put down with these heads.Cam specs are 246/250 627/633 lift on a 112 with KOOKS 1 7/8 headers no cats texas speed X pipe.Fast 90 intake with nick williams 90mm throttle body. tsp 100mm maf and speedincs chris 1313 ram air ac delete and ftp 104 mm lid slp pulley .My 6 spd 408 is on 11.1 compression
Last edited by wicked z28; 12-18-2010 at 07:23 PM.
