The idea that HEI systems are service-free is a myth. I've seen numerous HEI's with the centrifugal advance system totally worn out or locked up due to rust. A good high film strength lubricant needs to be used on advance parts and checked periodically, at least once a year on most systems. Just pull the distributor cap and rotor and check the weights and springs for wear, and dab a little high-temp grease on the pivot points. Ditto on the vacuum advance- - - -if it moves, it's good, but it takes a MightyVac pump or at least some mouth-powered suction on a piece of tubing to check for diaphragm leaks.
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!