When you static set the timing on a front mount distributer, you are actually setting
it at 4 degrees before top dead center. (TDC) The same as for the side mount
distributer. WHY? Because gasoline does not actually explode, It burns very fast
especially under compression. (The same for gun powder) That is why you set the points before TDC at 400 RPM. When the engine turns over faster the mechanical advance
moves the timing faster to compensate for the piston moving faster. Too much spark
advance can cause knock and if ignored can burn a hole in the top of the piston.
(I know that from experience on a 1950 Chevy PU). Too slow of timing can cause over heating because too much fuel is burning on the exhaust stroke. Ask a old Ford model T man when
they had the spark advance on the steering Colum. If you forgot to advance spark after it is running it would over heat. Retarding spark while starting helped in starting and may save a broken wrist if hand cranking