[rotorwrench]

To be a 12-volt system, It has to have a 12-volt generator or alternator and a 12-volt battery. Conversion requires replacement of all bulbs from 6-volt to 12-volt. Electric motors for the heater and the horn vibrators may need voltage dropping resistors. The gauges and the ignition coil also need voltage drops such as runtz type constant voltage regulator devices and ballast resistors respectively. The runtz product is what Randy Rundle calls his CVRs at the 5th Avenue Internet Garage web site. A person can purchase these or make them yourself if you know how to solder. Randy also carries the dropping resistors but he's not the only source. It takes a while to do a complete conversion. Working on the dash components are the hard part. Old radios with a standard vibrator will work on negative ground systems but they will need a voltage drop as well. Solid state radios are polarity sensitive.

All of the bulbs of 6-volt origin have a 12-volt counterpart that will fit in the sockets and headlamp buckets. A person just needs to know what part numbers to look for. Find out what kind of generator or alternator it has and that will likely be the best clue as to what the current status is. There are also converted alternators for 6-volt positive ground or ones that are made to look like a generator so look carefully.

The previous owner is the one to ask about this stuff. If he doesn't know then find out who did his work for him and ask them.

FYI: 12-volt lamps and bulbs will be very dim on 6-volt source. 6-Volt bulbs will quickly burn out on a 12-volt power source.

Welcome to the barn.