hey guys, 100LL (av gas won't really hurt your engine, but it doesn't make power. It is formulated to light( weighs less then pump gas per gallon) I won't go into the heavy/light molecule formulation.
I haven't dyno tested it on small engines but on a 300hp street stock small block chev we lost 18hp on the dyno with 100LL.
We run up to 12.6:1 on premium (only on bigger HP machines, you don't want to be able to bog the thing down with that much comp. Combustion chamber and piston must be properly blended and polished) 11-11.6:1 is real safe on pump gas.
Here is a video clip of one of our trail Raptor,s 12.6:1 on pump gas.

Ray
Raptor video

 

Wow-- you get a gold star by your name...........

 

Hey Hozed- 11:1 and ya oughta be fine on premium pump gas...