[Dave at Pelican Parts]

Compression and cam choice very definitely affect each other. With a wild lumpy cam, you can afford (and need!) a higher static compression ratio than with a mild cam. You can run higher compression when you use higher-octane fuel, so the people out on the east coast where they can get real 93 and 94 octane can run higher compression than we in California with our crappy 91.

Automotive engineering has come a long way since the mid-60s when the Type IV engine was designed. Flow theory, combustion theory, fuel mixture and spark control, materials, and on and on and on. Not to mention the whole water-cooling bit... The wonder isn't that we can't run the same compression as modern cars, but that we can get as close as we do!!

8.5:1 should be just fine with a stock cam on 91 octane fuel. 9:1 should be doable with 93 or 94 octane, and if you go to a lumpy cam grind you can get to 9.5:1 with the good fuel. Higher is possible, but depends on a whole lot of things.

--DD