too mild camshaft

the problem is that i dont know the compression ratio exactly! wich is very bad by the way. But im going to count it out. But i now its rather low on compression that i now for sure . the engine is dynoed in a superflow bench and ran on shell v-power 99 octan gasoline and the wieght on car is 3400 lbs. i have been thinking of milling my heads for the compression but i dont want to go over 12-1 compression because i want to drive on v-power gasoline because that is ordinary gas station gasoline that i cheap.. thanks for all of your answers