I've worked on a lot of worn out HEI's that the installer believed were "install it and forget it" items. The centrifugal advance weights and their pivot pins were worn beyond repair. Anything with any sort of mechanical component to it needs an occasional inspection and lubrication. A BB-sized dab of high temperature wheel bearing grease on the pivot pins would have prevented the wear, but those guys were too lazy to remove the distributor rotor about once a year. Ob the racing HEI's I built, I made bronze bushings for the pivot pins and opened up the holes in the weights to fit them for a much more predictable advance curve.
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!