head gasket thickness and compression ratio
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Joined: Jul 1999
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From: franklin, indiana
Car: '92 RS
Engine: 350+
Transmission: 700r4+
Axle/Gears: 3.73
head gasket thickness and compression ratio
so it is time to replace my existing head gasket. i have univergal gm 350 crate engine. it is a stock bottom end with a standard bore. my heads are a pair of iron eagles with 64cc combustion chamber. my question is what thickness should i look for in the optimal head gasket and what will be the resulting compression ratio?
i am sure that a similar question has been asked before, so if you guys do not feel like responding, could you at least point me in the direction of the correct thread? i could not find it on my own. thanks.
i am sure that a similar question has been asked before, so if you guys do not feel like responding, could you at least point me in the direction of the correct thread? i could not find it on my own. thanks.
Re: head gasket thickness and compression ratio
Certainly thinner is going to be better in this case, for building compression.
If you go with a common composition-style head gasket (very easy to seal up even if things aren't perfectly flat) you'll find most are rather thick- around .040" or more. With a gasket of that type, like they typical FelPro Blue rebuilder gasket your new compression ratio will be around 8.95:1.
The thinnest composition-style head gasket available is the GMPP .028" compressed thickness gasket. With this gasket you'll be at 9.2:1. Here is the link to that gasket:
http://www.sdparts.com/product/10105...eadGasket.aspx
They claim it's for stock and mildly modified applications, but I've used it up to 500HP myself personally with no issues whatsoever. It's a tough little bugger.
Now, if you want to go REAL thin, then you're talking about a steel-shim style gasket. They are less forgiving of parts that aren't perfectly flat, but newere designs like the Fel Pro 1094 have o-rings embedded in them that help mitigate this. With one of these gaskets you'd be around 9.4:1.
If you go with a common composition-style head gasket (very easy to seal up even if things aren't perfectly flat) you'll find most are rather thick- around .040" or more. With a gasket of that type, like they typical FelPro Blue rebuilder gasket your new compression ratio will be around 8.95:1.
The thinnest composition-style head gasket available is the GMPP .028" compressed thickness gasket. With this gasket you'll be at 9.2:1. Here is the link to that gasket:
http://www.sdparts.com/product/10105...eadGasket.aspx
They claim it's for stock and mildly modified applications, but I've used it up to 500HP myself personally with no issues whatsoever. It's a tough little bugger.
Now, if you want to go REAL thin, then you're talking about a steel-shim style gasket. They are less forgiving of parts that aren't perfectly flat, but newere designs like the Fel Pro 1094 have o-rings embedded in them that help mitigate this. With one of these gaskets you'd be around 9.4:1.
Last edited by Damon; Jun 29, 2008 at 07:01 AM.
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