I did say "not much difference" at the pump not zero difference. Ofcourse when pushing compression octane is important...but not at 9.5:1. I thought we were talking about your stroker sb mopar not your Harley.
I was just using the two as examples for octain sensitivity... I thought 9:1 is pushing it with open chambers running 87oct. I was told you can usually go a .5 a point higher with closed chambers because of the quench with dished pistons. You make it sound as if 9.5:1 is no big deal on 89oct for a 6k lb 4x4? Could I run 10:1 w/ 91oct? What cam do you suggest. Are you indeed Brian at Imm engines.