The harness on my '51 used woven cloth covered wire with vinyl tape wrap, except that the starter to ignition & ammeter and fuel sender to gauge harnesses were covered with woven cloth. I tried to replicate those particular harnesses with woven cloth covering but couldn't couldn't find that individually, so settled on modern plastic mesh covering. Rhode Island Wiring told me that the cloth harness covering is woven on to the harness. They have replacement harnesses for everything on your truck, but $$$$$$. IIRC the 2-wire Starter to Ignition & ammeter harness was $95.
