The best bet would be to replace the entire breaker plate, which is attached with four machine screws through the distributor housing into threaded tabs on the plate. Plenty of "core" distributors with suitable breaker plates can be found on Ebay for reasonable prices, as that design fits engines for many years of production. A "parts wanted" ad in the swap meet might even score you a freebie!
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!