9:1.
A good 454 will have at least 150 PSI per cylinder.
7.9 to 1
8.5 to 1 compression is factory stock.
10.5-1
Compression ratio on a 1974 Chevy 350 in a Nova was 8.5:1.
8.3:1 is stock
The compression ratio of a 350 Chevy engine usually ranges from 8.0 and 9.0 to 1. This provides a good balance of fuel economy and power.
with higher compression pistons
YES. That is a direct bolt on with no problems. The heads will bolt on, but the compression ratio will be different. Depending on which heads and which pistons, the compression ratio could be a lot different.
Need to know what size engine it has to answer correctly.
Answer GO TO YOUR CHEVY DEALERSHIP & ASKUsually the ft. lbs. on a intake and heads is 90 lbs. But just go to a mechanic and he can tell you. It also has to do with the compression ratio of motor too. I assume the ratio is probably no more than 8.0 on a '77, I know for a big block 454 the ratio was 9.5 factory on the older vettes. But hell a good Chevy man should know this right off the bat!