I'm running 10.2 to 1 that cranks 200 psi on both my Magnum and stroked 493" RB motors. I'm able to run full advance on both motors burning the 91 octane ethanol additive fuel we get he in California with zero detonation. My RB is actually locked out at 35*, and it never even kicks back on start-up.

While the 101 octane street legal race gas that's available at the pump nearby smells way better when burned, it's supposed to make less power than the 91 octane pump gas. The difference is so subtle that I can't feel it in either car.