Originally Posted by 6PakBee
Hmm. I really doubt that absence of cooling overheated a small part of the head. The comparison I was talking of was between 440-1 heads. Have you talked to Indy to get a dimension on a head bolt boss? I still think you should nail down just how much has been taken off the face. Otherwise I fear you may end up chasing your tail. twocents

Thought, according to Mancini, the as delivered chamber cc is 75 cc and can be milled to 62 cc. What is your chamber cc? This may give you an idea of where you are.

At the bolt area, below the exhaust ports my heads are now . 868 thick and . 862 thick. Chambers have been opened up some for a 4.50 bore, plus other work. Different valve sizes from original. It is hard to know how much the chamber volumes were increased doing that. I think the best plan is to just use them on a large low compression deal. I could build a 604 with 11/1 compression by reusing the block , pistons etc from the 550 combo with a 4.75 crank.

8..603 156 mph best, 2905 lbs 549, indy 572-13, alky