9.5-1 can be reached,depending on bore size with a closed chamber cyl hd @80cc's. 5 to 7 cc dome (off the top of my head )would allow 10.5-1.That is a very small dome that I have used before (Ross) 4.280 bore 0 [Email]deck@9.968[/Email] with 84 cc Eddies and 5 cc dome 10.7-1 .040 quench.
Curious what calculator you use , I have a 383 with a piston at zero , 3cc valve reliefs, steel shim head gasket and 80 cc heads and I'm just over 10 , I think 10.2 ?
