I'm sure it's been done many times, and someone will probably jump in here to answer you. The main thing to remember is that the car is positive ground.

Not to be impertinent, but....why do you want to switch over? Are you putting in modern accessories that require 12 volts? (I've been running my '37 on 6 volts for 43 years with no problems...but I don't have any modern accessories to run.)

That looks like the "Duke" Marley truck. Saw it when it was "under construction."

Have had my generator and starter rebuilt for 12 volts by a compay out it Phoenix. If I remember I will drop the name back here. Cost was about $190 each. I've been told that there is no need to change the wiring and to jiust change the bulbs. I would think a new voltage regulator and coil would be needed. Might need to drop the voltage for a couple of the guages but not sure.

Gordon,

You could keep the existing coil by putting a resistor in series with it. A conveniently mountable resistor was used on the Honda Civic from 1973 to 1979, and Honda Accord from 1976 to 1978. These cars had points. I have used the coil from these cars in 6 volt cars (without the resistor). This resistor should still be available from NAPA or other parts stores.

Assuming your headlights are original, it would be worth checking to see if anyone has made up 12 volt bulbs with the right base. The original bulb specified for my 1935 Hudson is #2320, which has 32 and 21 candlepower (cp). More powerful bulbs were also made with the same base. These are #2330, which is 32 cp for both high beam and low beam, and #2530 which is 50 and 32 cp.

If no suitable 12 volt bulb is available, you could put resistors in series with the headlights.

Per

And of course there is a special quartz halogen bulb that fits in the original headlight socket as well, but it's 6 volt.

Gordon,

This assumes that you still have the original reflectors and bulbs. If the lights have been converted to sealed beams, there's no problem!
The 12 volt large round sealed beams are the same size as the 6 volt sealed beams.

Per

My sealed beams with directional came in.Also have a nice up grade kit that looks great.