9.5 to 1 properly carbed and timed/curved dist. Some guys run higher on 93 with no problems. Most larger duration cams have lower cylinder pressures and one can get away with more compression
Stick to 9 to 9.5 and 93.
I build my engines as from factory and run only 104-110 octane. There are others that run their motors at the threshold of detonation that can really get detailed.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
