The best possible choice is the pre-computer HEI with the 4-pin module and the vacuum advance if you're running a carbureted engine. If it's wired for the full-function computer and port or TBI injection, use the electronic timing control HEI distributor that matches the year of the injection system and the computer. Aftermarket injection/HEI systems are sucker bait.
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!