Avoiding Pinging with 91 Octane California Gas

[jhirasak]

I originally built my SBF 331 cu in engine to run on 93 octane pump gas with 10 to 1 compression ratio aluminum heads and .041 quench clearance. My best engine performance was obtained with 16 degrees initial ignition advance and 36 degrees total advance by 3000 rpm. After I moved to California, I could only obtain 91 octane Shell premium pump gas on a regular basis so I first retarded my timing to avoid spark knock. This led to a noticeable loss in power, lack of crispness in throttle response, and slightly elevated engine running temperature. To regain performance and return to my original ignition timing with 91 octane pump gas, I have resorted to using octane booster additive with each refueling as well as slightly increasing the richness of my air/fuel ratio.

Without changing my compression ratio, I would like ask the forum questions regarding my options for regaining the performance that I had while using 93 octane gas.

1) Is there another brand of readily available California pump gas that is better than Shell premium?
2) What brand of Octane Booster provides the best increase in the octane rating of pump gas?
3) Other options?

Comments?

John