Classic/Antique Car Repair: 1948 International Pick up conversion 6 to 12 volts, volt conversion, volt system

Question
Rebuilding my'48 International KB1 pickup and going to a 12 volt system instead of 6, but I need to stay with 6 volts on the original oil, gas, temp gages. I have done this by using resistors. However, what do I need to do to use the original ammeter??

Answer
If your 12 volt installation has the output of the alternator wired direct to the battery the amp meter is then bypassed and will not show a charge rate. I would not recommend running the alternator through the ammeter and as much you might not want to do it I would recommend an accessory voltmeter be installed somewhere in the truck. I just finished a rewire project on a nice 49 Chevrolet including a 12 volt conversion for a customer. I used one of those "gage pods" that can be bought in most auto parts stores and mounted it with a voltmeter on the drivers side windshield pillar post. It blended in when painted the same color as the dash.