Cylinder Head CC size?
Team Owner
Joined: Sep 2001
Posts: 62,160
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
84-86E heads all have 76cc combustion chambers, it is the later aluminum head that got the small chamber
Thread Starter
Instructor
Joined: Dec 2004
Posts: 142
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What was the stock compression ratio on these engines? I ask because a friend is looking at 62 cc combustion chamber Trickflow heads to put on and I want to make sure his compression will stay okay for pump gas.
His engine is .030 over, and I believe his gasket height is .028
His engine is .030 over, and I believe his gasket height is .028
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
The compression ratio was 9.0:1. You can do the math to figure the non-swept volume. Then subtract the (76 - 62 =) 14 ccs from the non-swept volume to figure the compression ratio with the new heads.
RACE ON!!!
RACE ON!!!
Instructor
Joined: May 2005
Posts: 132
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From: Torrington CT
My 85 were supposed to have 76's to.numbers said so. Some where in the past they were worked on. Had them back on and the guys could not figure out why the car knocked. They had to pull it apart and found the 76's had turned into 67's . they swore they couldn't be but measuring with liquid doesn't lie. you might want to pass that on for what its worth.
