Honestly I didn’t have a number in mind as I run alcohol. I probably wouldn’t have even ran the numbers but a couple of guys were curious in my 408 engine post. I believe I will be truly testing the strength of a stock block with this compression and 325cfm heads.
I have a .100 flat dome on my Ross Pistons .005 out of the hole,.040 Cometic and a 67 cc chamber and mine came out to 12.7:1(cast iron head w2). You got more dome than that and a smaller chamber.