BigTex

iTrader: (16)

Yes, they are expensive.

You are raising your compression by using those .040 Cometics. If they have the same bore as the stock gasket, then your compression ratio has gone from 9.4:1 to roughly 9.8:1. Not exactly the right move for forced induction.

You should really get some stock thickness GM gaskets for this motor. BenKey found a set of stock replacements at a normal parts store. They were FelPro brand, graphite .060 thickness.

You could sell the Cometics (or trade me for my stock GM MLS 6L gaskets and cash).

marc_w

Good grief... You didn't hold back, huh?!

Like Sleeper said, it's on a 115LSA, with 1* of advance ground in. I'm pretty sure you'll still get some lope out of this thing with that duration an lift.

Should run like an animal in a stock 6.0... be sure to let us know.

BigTex

iTrader: (16)

Also, with a .600 lift cam, wide duration, and a -.02 lowering move of the valves, you may have some piston / valve clearance issues.

parish8

iTrader: (6)

i thought stock gasket was .042, your telling me .002 drop in thickness is that much increase in compresion? i need to look into that.

parish8

iTrader: (6)

damn, tex is right, hmm, now i got a decision to make, i dont want the felpro's, some stock mls would be cool if anyone has them in stock.

i might just run it with the 9.8 compresion, qmp is running 10.1 compresion and geting crazy numbers, i am only looking to run this thing for 6 months or so, then the 409 goes in. hmmmmm

whitt1

Parish the 114intake centerline is a method of degreeing your camshaft the peak lift on your intake lobe should occur 114 degrees after TDC.

BigTex

iTrader: (16)

first time for everything.


Take a look at some threads in the internal section about having to fly cut pistons with big cams. You are nearing that territory with the thinner gaskets.

I have a set of MLS gaskets.

whitt1

I thought that stock head gaskets compressed to .059",I think with the cam you are running the compression ratio won't be nearly as important as it would be with a stock cam the increased lift and duration will lower your actual working compression ratio,the calculated compression shouldn't matter.

parish8

iTrader: (6)

ok, i just checked the compresed thickness of those all ready instaled cometics and it is exactly .040. the only assembeled motor i have here is the 4.8 and it has the mls gaskets, the compresed thickness is .046. not sure if the 6.0 gaskets are thicker or what but not and there is really only a .006 diference then i wont mess with it, still looking for more info.

gota wonder if "ignorance is bliss"

parish8

iTrader: (6)

i wonder if the dish pistons will help with that? there is no interfearance right now when i turn over the motor.

i think i will run these gaskets. i just measured the 4.8 head gasket thickness and it is .046 and it is a mls gasket. the cometics are exactly .040 like the package says. even if it is 9.8-1 compresion that means it should run damn hard right now, have to limit myslef to 6-7psi when the turbo shows unless i have some good gas.