if you want an original looking conversion, you need a generator and voltage regulator that is 12 volt negative ground, like a 1960 chevrolet truck. Might be $150. if you want the cheapest version and dont care that it "looks " different, then get a 12 volt alternator with internal voltage regulator. You can get a Delco 10SI used on a 1975 chevy truck at auto zone for $35.00 Takes a little wiring, but not much. The starter will not know the difference. You will need a 12 volt coil or a dropping resistor to keep the coil and points in distributor from frying. That might cost an extra $20.00 Remember all the light bulbs will need changed. If you decide to go with alternator and need a diagraom, just post again. Make sure if you use an alternator it has the internal regulator. This is the type wiht two spade terminals "in line" on the side of the alternator. If the terminals are "side by side" This is the older version and needs an external regulator just like the generators.

I do need a wiring diagram please for 12 volt alternator. Thanks.
BJ