Hey Red58,
Hate to disagree withya on the "vinyl" thing but it's been around since the early 20's when a guy discovered it while trying to formulate synthetic rubber. It was used during the 30's and 40's for electrical wiring on aircraft/ships, etc and finally came into use on vehicles in the mid 50's. Maybe even 1954.
The "splice" I mentioned was where the 5 instrument cluster lights are tied together with a small metal collar and soldered, wrapped with friction tape and the entire loom was wrapped with a 3/4" wide, non-adhesive vinyl tape from the factory that I still can't identify.
Not the factory....but the tape!
Thanks for your input and stay warm up there!!!