[Smitty]

I am running 12-v in my coupe. Change out coil, bulbs, and while a 6 volt starter will work it slams pretty hard. Mine eventually took its tool on starter drives both modern and original. I am now running a starter re-wired for 12 volts and works a lot better. Converted to 12-v negative ground (need to make ammeter wire switch in the dash) and added resistor to horn. Everything is fine now, car runs a lot better and lights are a lot brighter. I run a 12-v alternator (1-wire type) which is available cheap in any auto parts store. Just need to change-out the pulley.
Steve