Holy cow! Corner Brook! I was through there in September, on my way to St. Joseph's Cove.
There's a diagram of the wiring in the shop manual,
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm1203.htmNow, I think you'd be better off buying a pre-made plastic harness from one of the vendors, like Jim Carter's or Chevs of the 40s. They aren't that much, when you consider how much easier it will make your life! Spools of wire aren't cheap either!