Problem is you can't get any low compression pistons for the 327 anymore without paying through the nose for them (400 bucks for KB hypers). With 64cc chambers, you need a 13cc dish to make a 9.00:1 motor that will run on 87 octane gasoline.

I'd start with a standard bore 350 short block. Parts are cheap and readily available. 18cc dish pistons will make 9.1:1 SCR with 64cc chambers.