Reply to "compression ratio"

First, please remember you're dealing with a 32-yr-old engine thats survived god-knows-how-many rebuilds, each of which will change the combustion chamber volume and c.r. Clean-up bores with new pistons do the same. So as-new info on possible engine combos are likely not to be of any value except to mislead you. There is NO reliable way to find out what you want without gritting your teeth and reaching for the wrenches. Once the heads are off, you can cc them and possibly the pistons also. 351-C pistons were once commonly available with dish, flat-top or domes, all of which influence compression ratio. I have a set of hardly-used 351-C domed pistons that delivered 9-1/2: 1 in open chamber heads & 12:1 in closed-chamber heads.

Bob, the Holley 600 vacuum-secondary carb is SO different from the Autolite carb that even the intake gaskets won't reliably interchange. For openers, the Autolite has a monolithic carb top similar to a Rochester Q-jet; which, once removed, exposes both floats & bowls from above. The Holley has dual cup-shaped float bowls hung on both ends of the carb body. IMHO, only die-hard purists and period-correct restorers will spend time searching out parts to rebuild these obscure carbs. Sorry.