A closer look at six-volt to 12-volt conversions
On a recent TV restoration program a car was being converted from six volts to 12. The restorer stated that in switching to 12 volts, all gauges had to be upgraded to 12 volts. I disagree. I converted a ’55 Ford from 6 to 12 volts. The voltage regulator, generator and starter were switched to 12- volt products, as was every light bulb.
The radio is operated with a step-down ceramic resistor. A word of caution here, you should place the ceramic resistor away from anything combustible, as it gets quite hot.
The clock was not working, so that was not an issue. I continued using the 6-volt battery cables. Perhaps it was because of my ignorance that I didn’t think of swapping the gauges, so they remained original.
I drove the car for three years and parked it for another three years, driving it occasionally, with no trouble with any of the gauges. Even the fuel sender continued to register correctly.
There is certainly no need to change out your gauges when converting from six to 12 volts. Runtz resistors that go for about $18 each are all you need to convert them over safely. These are small, easy-to-attach solid-state devices that produce no heat and will make your gauges read accurately.
It is good that you converted over your generator and starter motors, but you could have gotten away with just doing the generator. Your original six-volt starter will work just fine unless you grind away on a starter endlessly when your car won’t start, which will damage any starter, run down your battery and generally prove futile.
Your amp gauge will work just fine as it is, and so will your horns. They will just be a little louder. If you don’t like the sound, you can get horns off of a 1956 model, which look the same. In fact, things like your cigarette lighter and the like can easily be replaced with 1956 Ford components. Just save your old knobs.
As for wiring, six-volt wiring works great with 12 volts because it is roughly twice the size of 12-volt wiring. If you want more information, I suggest you buy a pamphlet called the official 12-Volt Conversion Guide by Randy Rundle, who also sells all the components you need to convert a car over to 12 volts. Here is the contact information: