Help with Flathead Ford F-4 Truck

If it was me and the wiring harness looks pretty good, I would leave that pup as close to stock as I could. Nothing wrong with a 6 volt system. It worked then, it'll work now. The 8 volt batree upgrade won't hurt a thing, though. If all the company wants is a cool advertising piece, the most economical way will be as few mods as possible.