Mike86Z28

What is the compression ratio of a 79 Chevy truck 350? Any websites ya'll can direct me to so I can find out more info?

RB83L69

~8.5:1

You found this website... What info would you like?

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"So many Mustangs, so little time..."
ICON Motorsports

bhaas

I have a 1979 350 truck motor in my Camaro.
8.5:1 seems kinda low. It doesn't have the original heads. Would that make any difference? What kind of compression should I expect on a compression tester?

Thanks.

RB83L69

Since heads are one of the 2 things that have the biggest impact on the static compression ratio, then if yours aren't the original, your CR might be different. Whether it seems low or not, 8½:1 is what those motors had; that's a big part of why they're such pigs in their original trim.

That motor came with dished pistons and 76cc heads, just like millions of other 350s from the mid and late 70s. It was a terrible motor in its factory form, rated at 185 HP IIRC. It's a very familiar motor. I have had several cars that had it, and so have my friends & family; it came in everything from Novas to Impalas to Monte Carlos to trucks to Z28s. It was sort of the universal Chevrolet motor for a number of years.

Compression tester reading vary widely, being affected by a huge number of factors, from cam profile to engine temp. Typical numbers for that motor as it came from the factory were in the 170 psi neighborhood, with the engine completely cool. Yours could be considerably different from that, depending on the particular heads that you have.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited January 28, 2001).]