Think of it like this....you advance the timing/increase comp to make power---you use a higher octane fuel to compensate for the advanced timing (if your at the threshold of your CR on pump fuel)----therefore (and I`ve seen this on a dyno) for every point of octane you are using that you DON`T NEED, your actually retarding the timing and LOSING horsepower. Octane is just to keep detonation (pre-ignition) at bay. Using an octane level that you don`t need is not only a waste of money, but a substantial loss of HP/torque! THX-1138 is right on, the only ways fuel can make you power is: if your not using a high enough octane for you CR/timing in the first place or if you are dealing with oxygenated fuels like the VP MR series. Nitro and alky are cool too! :twisted: