6v system w/ generator and you say you've bought everything from Classic...did you buy their $150 harness? If so, the instructions are perfect and they make wiring a super easy task. I saved mine and labeled what color corresponds with which number just in case I ever need to refer to it and the numbers have worn off.
The only thing I'd add to what everyone else said...replace the main power cable (1ga) and both ground straps while you're at it.
My blog entries on rewiring and main cables -
http://rustyfiftyone.com/category/electrical/
