Does any body know anything about these heads? (GM PART # 88958622) They say with a asa camshaft they should be near 500hp. Why are they "race only" Is gm just covering it's A from the smog laws or is their a real reason. I was wondering if its just a lingenfelter head. I am looking to get near 500 flywheel horse power. My current mods are asa cam and lg pros. when I do the heads I was going to do a fast intake as well. I'm also interisted in the Katech stage 2 heads as well. Too many choices The car is street driven and tracked, not drag raced much. Thanks
http://www.gmgoodwrench.com/perfpart...283&section=ep
http://www.gmpartsdirect.com/results.cfm
http://www.katechengines.com/street_...etail.php?id=7

 

The # 88958622 heads you are referring to are cnc ported by LPE for GM Racing. They are milled .055" for a 60cc cumbustion chamber. Here's a link to SDPC and these heads ->http://www.sdpc2000.com/catalog/1979...cc-Chamber.htm

My understanding is they were designed by GM for the World Challenge series. Rules limited Lift and valve size (stock). They are designed/flowed to with the Grand Am cam ( 239/251. 0.570", 106 lsa ).

I run these heads along with the GA cam. With 2.02", 1.57" valves and handsanding they flowed 312 cfm on LPEs bench. RWHP = 445 through 4.10s. Close to 500 HP at the crank.
In manufacturing they are welded ( intake port roof cyl 5 or 7?) prior to cncing -> which has created a problem area - breakage- for some .
Mine have been fine.

I think the Katech heads look like a pretty good deal.

You might take a serious look at ETPs LS1 heads.
Here is their 225c GIII head:
Cylinder Head: G III LS1 11° Application: Street / Race
Port Volume: 225cc Chamber Volume: 35cc to 72cc
Test Bore: 4.000" Test Pressure: 28.00" Water
Intake Valve: 2.080" Exhaust Valve: 1.570"

Valve Lift Intake Exhaust Valve Lift
.100" 71 57 .100"
.200" 153 114 .200"
.300" 208 164 .300"
.400" 265 204 .400"
.500" 308 224 .500"
.550" 320 228 .550"
.600" 328 231 .600"
.650" 332 234 .650"
.700" 320 236 .700"

Exhaust to Intake Flow Ratio 73%

Jobber Price: $2,325.00 · Retail Price $2,475.95

Here's a link->> http://www.etheads.com/mainpage.htm

 

I am running these heads on my car, with a TR 232 237 .594 .602 11+4 (from cam card) and put down 460 428 sae. I am very happy with them, and we could put a bigger cam in (intake esp and even a bit more on ex) but PVC was tight. There is more to be had with a 90 90 too. Nice heads
Dave

 

The orignal reasons I was interisted in them was reliabilty and The fact that I can get them through my dealership. Since GM and Lingenfelter builds them I assume quality is top notch. My biggist question is, are they worth the money? My cr should be about 11 to 1 right? Also what head gaskets and what length/brand pushrods should I run? GM makes a mls (thicker,lower cr) and a triditonal (weaker?) head gasket,or should I go aftermarket for this? Thanks for all the help!

 

I think the CR is actually a tad over 11:1. 11.3:1, I think. Even if the MLS gasket is slightly thicker, you will still be around 11:1.
You need the 7.35 hardened pushrods with the milled version of these heads.

 

Use the later (MLS gasket) - that is the spec'd gasket by GM Racing.

 

Thanks Bink and Greg, any preferinces on what brand of pushrods?

 

Comp Cams Hi Techs or Manley's 3/8"s. Call S/D in Texas. they'll hook you up.

 

Trend is another brand.
I'm using the Comp Cams pushrods but they are 5/16" diameter which is the same O.D. as the stock pushrods. I don't know if there are any fitment issues with the larger diameter, and for street use I don't know why you would need the larger ones.

 

Thanks!

 

Thats what we went with, and they are TR (7.35) and GM MLS. I love these heads and you can realy see the work LPE does in the proting. Very nice. Next time myheads are off, I am sending them in to be hand polished, as i hear they come back like glass and aget a nice bump on top.
Dave

 

Mine are Comps Cams. 7.35"

Here are few pics of the LPE hand sanded heads with larger 2.02 and 1.57 valves.

 

Nice pix in your kitchen I have all my interior parts in a bedroom right now since I'm building a rool cage. Thanks for the pix. All the ones online are no good. Does anyone have any problems with the intake lining up since these heads are milled? Thats the only other thing I'm worried about. I want to go with a fast 90mm.

 

Are those GMPP or Cuisenart?

Nice looking heads

 

Milling .055" moves the alignment pin receptacles, on the heads, down and inwards - so you will probably need to shave a bit off the bottom (length) of the intake manifold pins. Check the manifold without the gaskets to insure it doesn't rock. If anything you want the pins short so they don't bottom out preventing a tight seal -> torque to spec - pound-inches, I think.
I had to adjust my LS6 Intake. No need on my 90 mm LSX.

 

The GMPP heads are also available in a 65CC chamber version if you want to keep the compression ratio below 11:1, I would recommend these (GM pn#88958665) for a street car, so you can comfortably run 92-93 octane fuel. At just over $1900.00 for the pair outright, you cannot beat this deal on genuine GM LS6 castings anywhere.

Let me know if I can answer any questions,
Ed

 

Very cool Mine where cleaned up but not hand sanded, and they looked great, but not that good. I would be a waste as mine are actualy in very good shape. Now if I can get a few 1/10ths off my ET I will be happy.
Dave :o

 

I just got the 65cc version and I am looking to cut them down to 62cc chambers. If I cut them down does the intake manifold have to be shaved?

 

I have the next step down from these on my car. The combustion volume is ACTUALLY 44cc according to the catalog and my GM rep. The 12480090 head (mine) has a combustion volume of 60.9cc and will make your comp ratio around 11.2. My car put down 450RWHP with these and a .228/.228 .590/.590 112 cam, L/T's, 30# SVO injectors and a cold air kit. I work for a dealer and if you need these I can hook you up!!

 

Thanks, Is detonation a big problem with the 60cc heads? I wil use the mls head gasket, at least thats are what people are recominding. The car no longer is my dd, just my toy. I don't mind it being a little radical on the street but if I track it I will put some 100 octane fuel in it. As long as I don't advance my timing too much I should be ok with the 60's right? If I go with the 65cc heads wil I lose much power? I wan't to keep the cr as high as I can and still drive it on pump gas, race it on 100. With the asa cam I would think it should blead off a lot of cylinder pressure and make it more pump gas freindly. Thanks for your expert opinion

Wow thats impresive, I would be very happy with 450rwhp. Since you have 61cc heads, how is it on pump gas? Thanks for the offer but I too work at a dealership that sells cadalic. Thats what got me interisted in the heads and then I found out Lingenfelter did all the work.