You don't have to run higher compression or timing; but you won't get the full benefit of running alky if you don't. Is the motor ported? Not much to be gained on a non-ported motor. It can give you about 7% more hp, so If you've only got 40 or 50, it ain't worth the headache for 3 hp. It does run much cooler than gas, though - that can be a benefit; but you use twice as much, so you won't get very many miles per tank.