Can you put a 350 Chevy engine in a 1980 cutlass supreme?
The 305 was an option on that car, so a 350 should be a bolt-in.
They did not make a 400 sb Chevy in 1974. But from 1975 to 1980 they did and the answer to your question is 8.5:1 from 1975 to 1977 Then from 1977 to 1980 it was 8.3:1 ratio. That is Advertised compression ratio. I may stand corrected on the date when I said they did not make a 400SB. But The info. I gave you was all I could find. NEUTZ.