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Discussion Starter #1
Hi all, I just bought an all original 75 Camaro type LT with the original 350 engine with 185k miles. I took compression readings from each cylinder and I want to know if the readings are low and what do they mean...
Cylinder 1=110psi
2=120psi
3=110psi
4=120psi
5=110psi
6=120psi
7=110psi
8=120psi
What does this pattern mean?
 

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Discussion Starter #4
I used a threaded tester but did not hold the throttle open...I forgot. I'm trying to determine if I need to rebuild the engine...
 

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That pattern to me indicates that the compressed thickness of the head gasket differed slightly between the two heads. The ten psi higher on one bank indicates it was compressed a bit more, or more likely the head has been cut down to obtain a flat surface to seal the cylinders in the past.

'75 is a smog motor with reduced static compression compared to a 1970 engine (last production year to have a 64 cc chamber). New heads not only offer better breathing through improved port design and larger valves but it allows you to pick your compression chamber volume to raise your static compression (which raises horsepower but also raises the octane requirement of your fuel).

Big Dave
 

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Discussion Starter #6
Thanks big Dave,
I too was thinking about replacing the heads with performance models.
Thanks guys!
 

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