The vacuum advance goes away entirely when the engine is under load- - - -uphill, passing, trailer towing, etc. The only function of vacuum advance is to get better gas mileage at light throttle cruise. As soon as the throttle is tipped open even a little, the vacuum advance goes away and all that is left is centrifugal. I've had the best results with 32-34 degrees of initial plus centrifugal advance at 2500 RPM, (crankshaft, not distributor degrees) plus another 10 or so degrees from vacuum.
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
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