Head Gasket
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Joined: Dec 2004
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From: Kalamazoo MI
Head Gasket
I recently purchased a set of Edelbrock Performer RPM cylinder heads from a forum member. The heads are 170cc intake, 70cc combustion chamber. The heads that are on the car (86) are the 76cc C.I. It has been recommended that I use the Felpro 1010 head gaskets. Is this a good choice? I see that the 1010's compressed thickness is .039in. is that simular to the stock compessed thickness?
Thanks
Thanks
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Joined: Sep 2000
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From: The Top of Utah
No. Your stock head gaskets were .021" compressed. Using rough numbers, the 1010 gasket holds 9 cc (8.9). If the stock gasket at slightly better than half the thickness holds 4 1/2 cc, pessimistically you are only gaining 5 cc (probably closer to 4) due to gasket thickness, along with a 6 cc loss due to combustion chamber size, a net difference of 1 cc. I wouldn't be concerned with gasket thickness in thus application.
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Thread Starter
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Joined: Dec 2004
Posts: 82
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From: Kalamazoo MI
Thanks,
So if I were to want a little more compression I would want to use a gasket with a compressed thickness simular to the stock gasket. Do you have an idea what the cr would be with the stock gasket thickness? I currently run the base timing at 10 degrees advanced, and use 92 octane gas to prevent knock (overkill?).
So if I were to want a little more compression I would want to use a gasket with a compressed thickness simular to the stock gasket. Do you have an idea what the cr would be with the stock gasket thickness? I currently run the base timing at 10 degrees advanced, and use 92 octane gas to prevent knock (overkill?).
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Way overkill on a 9.0:1 engine. With the same heads and 9.0:1 compression, I run 14° base timing on 85 octane gasoline.
You can easily figure your compression with any number of changes. Work backward from what you know, 350 cid, 9.0:1 compression, with 76 cc heads, and calculate your clearance volume. Then adjust the clearance volume by the intended changes and re figure the new CR.
RACE ON!!!
You can easily figure your compression with any number of changes. Work backward from what you know, 350 cid, 9.0:1 compression, with 76 cc heads, and calculate your clearance volume. Then adjust the clearance volume by the intended changes and re figure the new CR.
RACE ON!!!
Thread Starter
Advanced
Joined: Dec 2004
Posts: 82
Likes: 0
From: Kalamazoo MI
No. Your stock head gaskets were .021" compressed. Using rough numbers, the 1010 gasket holds 9 cc (8.9). If the stock gasket at slightly better than half the thickness holds 4 1/2 cc, pessimistically you are only gaining 5 cc (probably closer to 4) due to gasket thickness, along with a 6 cc loss due to combustion chamber size, a net difference of 1 cc. I wouldn't be concerned with gasket thickness in thus application.
RACE ON!!!
RACE ON!!!
