[455-4+1]

I have a set prepared by Jim Robertson, he's probably had more set of these accross his bench than anyone lol.
We were after max compression for an iron headed 400 build, (as close to 14 as we could get).
If you look at the pics posted with a head gasket ring, vs a typical 72cc head, you will notice a difference. Short turn also.
Can't measure mine as the are on an engine at present, and we're Milled around or over 0.080" so no longer original, but they certainly started out alot less than 72cc.
From memory the ended up around 50cc.
I will try and dig out some pics

Formulas, you might want to check with your dog again..........