Having done 3 51-52s over the years here is what I found. First off plan on replacing all the original wiring, the original 60 year old cloth covered wire is a fire waiting to happen. If the switches are in good shape they all can be reused. As noted the coil will need to be changed (and make sure to use a ballast resistor).


"....Will the gauges work on 12 volts?...."

Of the 4 gauges, the fuel, temp and oil pressure will need a 12V to 6V voltage dropping resistor (available off E Bay) as these gauges use a common voltage source only one resistor is required. As far as the AMP meter it will work as is, but you need to know how to wire it. There is a loop on the back of the gauge and the main power wire from the generator (alternator) is threaded thru the loop. If you go with a 1 wire alternator the one wire from the alternator goes from it to the positive side of the battery. For the gauge to work that wire needs to be long enough to go from the alternator to the back of the gauge and then to the positive post of the battery (use at least a 10 gauge wire).

If the truck has a heater, you will want to either change the motor to 12V or use a separate dropping resistor for it.

The 51-2 could have either had vacuum or electric wipers. If you’re lucky and have electric wipers (and they still work) you will want to use a seperate 12 to 6 V resistor for this also. IF you have vacuum wipers you can either leave them (if you can live with it) or convert to electric (there are various kits on the market that may work).