Thinner head gaskets on a 88 5.7L

ericinga · Aug 19, 2018

I plan to pull the heads on my 88 5.7L. They are original and need to be rebuilt. The valve seals are leaking.

Rather than milling 0.10" off the heads to bump compression, I was thinking about using a thinner head gasket. The OEM replacement is 0.41" compressed. FelPro has a 0.25" gasket.

Anyone tried this change? Had issues with quench, piston to valve clearance, push rod angle?

TIA

Eric

c1500deathtrap · Aug 19, 2018

The composite ones gm uses stock are only .028 compressed thickness or so. so no, the fel pro .025 gasket will offer little to no bump in compression over what you had. https://www.summitracing.com/parts/nal-10105117/reviews/?filterReviews=ThreeStar <stock style for the TBI's and vortecs.

Schurkey · Aug 19, 2018

You'd do better to cut the block deck than to cut the head if you want more compression.
Wild Guess: Your pistons are 0.025--0.030 in the hole now. Add 0.028 gasket thickness, and you have no quench.

The LO5 pistons used in the Caprice are flat-tops instead of dish pistons used on the trucks. Another happy compression boost.

Given the crappy swirl-port heads, you might want to replace them instead of rebuilding them.

Thinner head gaskets on a 88 5.7L

ericinga

Newbie

c1500deathtrap

I try

Schurkey

Supporting Member

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