From my experience with PING monsters in hot Southeast Texas, I would go 9to1 I built my alum head 512 with quench at 9.7, just to be on the safe side.
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
