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The amount of timing advance to maximize power is a relatively complicated formula dependent upon several variables such as: RPM,,,,,Compression,,,,,Fuel and Octane. Thats why and how centrifugal (RPM based) advance and even vacuum advance come into play to change the timing relative to RPM and manifold vacuum. As RPM increases more advance is needed to initiate the combustion cycle far enough ahead of TDC so that once the piston just crosses past TDC the exploding gas pressures drive the piston down. At lower RPM's if the combustion is initiated too soon before TDC the exploding expanding gasses tend partly to drive the piston backwards which is a severe loss of the intended energy. At higher compressions it becomes necessary to use higher octane rated fuels which are more difficult to ignite (to prevent pre ignition) so higher RPM coupled with harder to ignite fuels requires more timing advance. You have to initiate the combustion cycle earlier at higher RPM's with fuel thats harder to ignite..... Sooooo ooo Im not smart enough to answer your question in any general one size fits all answer cuz the answer is IT DEPENDS. Maybe the best way is to couple her to a dyno and load her down to a typical horsepower load and at rated RPM then fine tune n tweak the timing to maximize horsepower for that fuel and that RPM and that load !!!!! !!!!! That may involve the use of different distributor weights and/or spring tensions to alter the advance versus RPM timing curve or maybe just tweak the distributors rotational position which adjusts the static start timing (when theres no centrifugal advance) but also obviously affects timing in general. John T in Indiana, retired electrical engineer NOT a mechanical engineer but we learned this stuff in the back of our EE books at Purdue in the good ol sixties lol
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