What octane should I run

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SOME HOLLEY CARB TIPS - Page 8 - PY Online Forums - Bringing the Pontiac Hobby Together

The engine dynoed was built to run Sonoco 112 BUT it made more power on Avgas because of the lower cylinder pressures UNTIL the rings finally ran themselves in and the cylinder pressure increased requiring the 112.

"AV-gas is a consistant fuel that is the same everywhere in the world and its the same all year and it evaporates easily inside the engine to create a good homogenous mixture throughout the cylinder. Av-gas has just about the highest energy content of any petrol, racing fuels or not. Race fuels are made from av-gas. Av-gas is the stuff to use. I dont understand why people wont tune to run it. It tunes to run nice at light load to keep cylinder condition correct for changes to WOT. Its easier to idle on the line with it. It is far more forgiving of a bad engine combination than street unleaded is. Its cheaper than race fuels."