I cc'ed my 3917215 heads today and here were the results.
1st head.....103,104,104,105
2nd head.....104,105,105,106

My question is: I was planning on using speed pro's 2240NF60 pistons which would give me a compression of 9.7:1 with a 101cc head. How much will that compression ratio change with the numbers I got? The heads have already been milled.

Run Pat Kelly's DCR calculator and see. I know that 4cc in my case goes from 10.5 to 10. 9.3 is my guess, but you should use a compression calculator. You'll need to know dome cc, head gasket thickness, and the deck height to do it right.

I guess a better question would be....Should I have these heads milled again to try to get them closer to the 101cc I need?

Interesting. My 290's finished at 104CC. I often wonder where the data came from for the combustion chambers. Have seen stock open chamer heads (adv at 118 CC ) as large as 123CC.

When I had them milled I was worried that I was under the 101cc. That is why I cc'ed them to see where they were at and to my suprise I was over.

Do you know how much the heads have already been milled?

I have heard that BBC iron heads can be milled quite abit, as much as .080". Don't know if this would create any issues with the sealing or strength of the heads or not.

I have had my 049's milled .040" with no problems. This took my heads from about 122cc down to 113-114cc.

You just have to make sure that you have the intake side milled also to make sure of proper intake manifold alignment.

They were milled .030 before I bought them and another .005 later due to a gouge between two of the chambers.

I am not surprised. My 215's came in at 104-105 after being shaved as well. Wish I had known that at the start. Would have changed my piston selection! Running a shim gasket to make up.

Mike