Ok so my 10:1 build is alot more knock limited than I thought. At 10psi Im already around 3degrees BTDC. I am running RC 550cc injectros and wanted to know if I could run E85 I read accouple forums where people have done so but not exactly sure. So my question is should I retard the spark and run 15 psi or will I be better off stuck at 10psi with E85?