[MikeK]

Originally Posted by old28

If you bore the (A) block .125 over and install a set of 3 ring pistons from Snyder with a milled stock head can you get 7.5 CR?

No. A stock head is 4.22:1 CR. Taking 0.100" off it (likely too much!) and then facing the .125 over piston tops so you have 0.040" squish clearance with a 7013 R3 compressed gasket will give you ~4.9:1 CR. Milling a stock A head is a losing proposition. Also, 0.125 overbore leaves you with a block that has very narrow siamese areas that will be prone to gasket blowout if you want to make more HP than stock.

You really need to talk to the HAMB guys on one of their banger threads.