I just did this on my friends 79. I converted his to 12 volt just because you can't find 6v stuff everywhere. The problem with the conversion is that there is not enough wattage to run the headlamp and the rest of the lights on just DC. So I had to put in a 12v AC regulator and wire the headlamp back into the original AC circuit. Works like a charm and is a simple and low cost conversion.