Is your truck positive ground? If so, that is another factor. I would suggest that a TF truck should be 12V neg ground. Your future life will be much better and you will a cool guy. It's pretty easy to accomplish. A 6V TF truck is a mistake of nature.(and GMC). Putting in a bunch of resistors and transformers and voltage limiters and reducers and expensive gadgets is silly and will lead to bad teeth. We have a wonderful tip section on converting. Rewiring
not required. BTW, I had a 56 GMC Carryall. Nicest looking truck I've had. Check out the "Solid Windows" tip for TF Carryall/Suburban....and this for Panels, Burbs and Carryalls:
http://www.hotrod.com/how-to/wheels-tires/1402-spare-tire-mount/Also from the experts in the "Radios" tip section is this:
Q. Can I use a 12V radio in my 6V truck?
Yes, if you can find a DC to DC converter to step the 6V up to 12, but it might be preferable to convert the truck electrical system to 12V.
