Vacuum advance is mostly there to give a gas mileage boost at very light throttle. An engine that's doing any pulling at all doesn't need it. Lots of industrial and/or truck engines had no vacuum advance at all. Such things as having a standard or automatic transmission, or even a different rear end ratio might require a different calibration of the advance springs- - - -both centrifugal (engine speed) and vacuum (throttle position/manifold vacuum). It's about equal parts of educated guesswork and voodoo in the automotive engineering world, plus a considerable amount of SWAG ("Scientific Wild-Donkey Guess")!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!