[cobragene]

I have a 428 bored .030 with performer heads 6006 from late 1990s, when the engine was completed comp ratio came in at 9.9-1 later I had an issue and the heads cut .004 . The head Literature says chambers are 72CC and each .005 cut reduces chamber volume by 1CC. Can anyone (Brent) tell me what comp. Would now be? Thank you