8.5 to 1 compression is factory stock.
8.3:1 is stock
6 to 8 degrees advanced. for stock compression ratio.
305 Small Block Chevy engines typically were 8.6 compression ratio and would use 87 octane fuel.
The stock compression ratio for a 2003 Yamaha YZ85 is approximately 8.6:1.
10.5-1
It varies from 145 to 370, depending on a lot of variables including compression ratio, cam profile, and head design.
Yes, they will fit on the block. The larger combustion chambers of the 307 heads will probably reduce the compression ratio by a fair amount, reducing power output.
11.3-1 stock piston with stock 3 layer base gasket
The stock compression ratio for a Suzuki QUV 620 is 10:3:1. Special spark plugs can increase that compression and the horsepower.
It is 8.54 ~ 10.12 :1
Compression ratio on a 1974 Chevy 350 in a Nova was 8.5:1.