Isopropyl/antifreeze........you're kidding right? What did E Gorr say was required to use with your head setup? Thats what it takes, no subsitute. You are right, octane boosters,etc are a waste of money and would only raise octane by a few points, and AvGas is no good either. You might get away with 50/50 93 and 106 but you better check what octane is required. Surely he told you huh? You should have expected this when you got head milled and been prepared to use race gas.