Those cars ran untold millions of miles, reliably, before Pertronix was even thought of. I've seen 25,000 volts from the coil secondary a 6 volt system. The ignition system didn't suddenly get weak from old age. Start at the ignition switch, and check the voltage drop through every connection. You've got a problem somewhere that you haven't found yet. The Pertronix would just be a band-aid on a brain tumor. Find your voltage drop!
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!