Another low budget 360 build

I actually worked out the numbers... The H405CP pistons are about .050" in the hole for a standard LA block and have 10 cc's worth of valve reliefs so are not high compression by any means. (BTW< the compression height is 1.675".) The OP's combo works out to 8.6 static CR with 72 cc head chambers, and 8.9 static CR with heads shaved to 68 cc chambers. Both of these numbers are with the .028" head gaskets.(I would not expect 65 cc open chambers; that is probably an NHRA minimum spec.)

Dynamic CR's will be 7.1 and 7.3 respectively with the Lunati 60402 cam. I can't see where the OP has anything to worry about with detonation at these levels and regular fuel and the mid 2000 rpm range stall TC.

Later on with closed chamber heads, there will be no effective quench with these pistons so that anti-detonation aid is out if the H405CP's are used. 63 cc closed chamber heads would push DCR to 7.7 with that cam so still has some margin against detonation although a cam change may be in order then, or aluminum heads would pretty much proof it against any such problems.

BTW, OP, I use the Pat Kelley calculator if you want to plug in numbers and see these results on your own.