My 56 shorthood has one of those things too, when it craps out my repair guy said just replace it with an alternator for a chevy 350, much more reliable supposedly, and less wiring too. I know some fellas that rebuild old 200's and that's all they do, the alternators are fairly cheap around $80-$100 canadian at partsource or napa, that would probably be around $70-$90 USD. I'm not sure if there's a partsource in the US as they're a division of canadian tire but I know Napa is there, anyways that's just what I hear good luck.