Gary U,
As you most likely know, the original 1954 wiring harness has plastic-coated wires, and black tape or black woven "sheathing".
Jim Carter and Classic parts sell original-style 54 harnesses at good prices and quality (with correct color-coded wiring).
Do you have any old wiring in place in the truck? If you do, just remove and replace, one harness/segment at a time. If you do not have any wiring in place, maybe someone else will post helpful advice.
You will most likely also want to buy rubber grommet(grommets ?) for where the harness comes through the firewall.
