I restored my wiring harness on my '51, adding turn signal wires heading to the parking lights. I used some non-adhesive vinyl tape that I got from Summit Racing
Link to re-wrap it so it looks very similar to the original harness. It takes 2 people to put it on, but not that hard. I've also used the split loom that Fibonachu linked to, as well as woven plastic (think chinese finger trap stuff).
link
