hey Lenz,i have 10.7 speed pro pistons in my 433,i think im around 11 to 1 actual. i was running half 93 and half 110 before i started having trouble.i had filled it up with 93 a couple times when it went haywire,but i couldnt link it to the bad gas till you guys brought it up,i think Jay brought it up right away,thanks