I used YNZ reproduction harnesses in my ‘37 coupe. They were very well made and clearly labeled for easy installation. I have heard good things about harnesses from Rhode Island Wiring.
While I agree that you can build your own functional harness it will never fit and look like a good reproduction harness. If you want to make your own reproduction harness be ready to spend a lot of time doing research to determine all the different terminals and wiring you need to order. And the cost for all the different items will surprise you. Typically there are minimum order quantities for those items. Then you will spend a lot of time building the harness.
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