jfnar, the compression ratio you pick depends on whether you are using iron or aluminum heads. Before you laugh, a "valve job" that puts used heads in like new condition (bronze guide liners, 3-angle valve seat regrind, centerless grind valve stems to restore roundness, grind valve faces, new springs, new valve seals, resurface gasket surface) can actually cost more than new heads. And with performance heads you also get nice bowl blending and screw in studs.
Iron heads at 9:1 will not tolerate 87 octane gas on a hot day if you are running a carburetor unless it is jetted way too rich for clean running and good power. My street roadster has 9:1 aluminum heads and it took some very careful carburetor and distributor calibration to avoid pinging on 89 octane.
There is a HUGE variety of small block Chevy heads out there with combustion chamber volumes from under 60cc up to 76cc. That range, in addition to the similar HUGE variety of pistons, will let you pick any compression ratio you want.
Supposedly one of the biggest bargains out there is vortec heads but there are some good versions and some ones to avoid.
If you're building an engine from scratch you can make it be anything you want it to be. Have fun!
