[Michael C Henry]

Alluminum heads give at least .5 break.( you didn't say. I'm at 11.5 -1.I have alluminum heads run pump gas but use an additive ment for motorcicyles. It came reccamended with the car from the original engine builder.I had a cam go flat and had the engine torn down ,no damage noticed. I haven't bought any racing gas yet. But plan on splashing some in the tank in the future.