When I bought my '53, I understood as much about electrical wireing as a kid in second grade.
The truck had been stripped of all wireing so there was nothing for me to go by.
The truck came with a wireing kit, but it was wadded up in a box, had no instructions, and no tags or labels.
I considered throwing the kit away and buying a new one just to have one with instructions and labels. I then found a wireing diagram, printed it out, and brought the box of wires in the house and strung it out all over the livingroom floor. after pushing wires around so that it started to look like the diagram, I bundled up the kit in different sections and took it out to the truck. After getting the wireing kit in the truck came the fun and easy part(I'm not kidding). Once you get started everything just starts to fall into place.
So even without instuctions, labels, or any prior experiance, I ...
rewired my truck
changed from positive to negative ground(GMC)
converted to 12 volt
and have't had a single problem.
Did I mention that it was winter and I don't have a garage? I would do it again in a heartbeat. Not only did it not cost me anything, but I also gained a little pride and a lot of knowledge.