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.
Compression ratio on a 1974 Chevy 350 in a Nova was 8.5:1.
8.5 to 1 compression is factory stock.
10.5-1
About 8.5 to 1
then youre running about 8.5:1 compression
Good compression, good heads, good cam.
4.000x3.750 with 8.5:1 compression
around 80 ft.llbs. or higher is usually good.
If any two adjacent cylinders have low compression it's probably caused by a blown head gasket.
It could be the timing chain/sprockets marks are not lined up correctly or the valves are not adjusted correctly.
head gaskets??? warped heads? did you have them milled?
The 1970 engine had higher compression, but the big difference is in the way horsepower was calculated. In actuality, the 1970 was only a little more powerful than the 1977.