Lots a folks said 10.8 static compression is to much for iron heads on pump 91 but I can tell you it's not.
When I go aluminum heads I'm gonna push pump gas even more. In fact I wanna push it right to the edge and maybe just a little bit past..
I ran my 10.6:1 5.9 magnum on 91 pump gas. Never had an issue and it ran GREAT. Had several people tell me it wouldn't work, but I did it anyways since those were the parts I had. I pulled it apart and didn't see any signs of detonation so it went back together with aluminum heads.
