Questions and Answers
Ford 351 Compression Specification
Q. What is normal compression on a Ford 351m400 for each cylinder? It's a 1978 2bbl changed to an Edlebrock 4bbl intake and Holley 650 carburetor?
A. Minimum compression is 100 psi @ 200 rpm. The lowest cylinder reading should not be less than 80% of the highest reading. Perform the compression test with engine at normal operating temperature, spark plugs removed and throttle wide open.
Normally I look for about 170 psi to 180 psi.