impala head gaskets
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
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From: Gainesville Fl
impala head gaskets
i have heard these give you a .3:1 bump in compression. Has anybody here done this? apperantly it is just a thinner gasket. is this safe to do? why are they different on the impala anyway? please help me out here
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
The Corvette head gasket is .049" and the Impala is .029". I've had them on mine for a couple of years with no problems. With the pistons I'm currently using they give me an 11.3:1 CR. Why the Impala used thinner gaskets, you'd have to ask GM's engineers I suppose.
Burning Brakes
Joined: Nov 2004
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The standard (for 56cc aluminum heads) LT1 headgasket is .039" thick. The Impalas had iron heads and used a thinner .029" head gasket, partially because these iron heads had larger (64cc) combustion chambers. Mechanics have valued this .010" difference at somewhere between .25 to .5 of a point of compression when used on an aluminum head LT1. I think the .3 is a good 'ballpark' estimation. I have used this gasket with no problem on a stock block with lightly shaved heads and high lift cam. It is a worthwhile consideration if you already have the heads off. It is common knowledge that GM's advertised compression ratios are somewhat overly optimistic, and when measured, usually come in a little lower than expected. So a little increase in compression is a good thing, in this case. TPIS sells them for $50 or $60 for a pair. I think SDPC also sells them.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by 500hp
The standard (for 56cc aluminum heads) LT1 headgasket is .039" thick. The Impalas had iron heads and used a thinner .029" head gasket, partially because these iron heads had larger (64cc) combustion chambers. Mechanics have valued this .010" difference at somewhere between .25 to .5 of a point of compression when used on an aluminum head LT1. I think the .3 is a good 'ballpark' estimation. I have used this gasket with no problem on a stock block with lightly shaved heads and high lift cam. It is a worthwhile consideration if you already have the heads off. It is common knowledge that GM's advertised compression ratios are somewhat overly optimistic, and when measured, usually come in a little lower than expected. So a little increase in compression is a good thing, in this case. TPIS sells them for $50 or $60 for a pair. I think SDPC also sells them.
Team Owner
Joined: Jan 2003
Posts: 20,335
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From: Summerland B.C. Canada
Originally Posted by Corvette Kid NC
The Corvette head gasket is .049" and the Impala is .029". I've had them on mine for a couple of years with no problems. With the pistons I'm currently using they give me an 11.3:1 CR. Why the Impala used thinner gaskets, you'd have to ask GM's engineers I suppose.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by AGENT 86
Yo Chris, whats your DCR if your static is 11.3:1
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