IML: reproduction wiring harnesses

I'll second Rhode Island Wiring Harnesses as being my choice. I've installed one in my '55 DeSoto and found it all went well. They also have the '54 Custom Imperial harness that they duped from my '54. They have a pretty good diagram with numbered connections that combined with your FSM diagram gets the job done.

As far as later harnesses, I got one from Greg Leggatt in Canada for my '62 Crown (currently in for upholstery at long last!). I was impressed that everywhere there was a screw post connection, he had wired on a new nut and in every socket there was a new bulb. I think you'll find him in the vendors section or look on the 300 club site. Neither of these coices is cheap, but but the alternative of working your own way thru the maze of wiring is daunting. Of course, you could always do like the previous owner of my '56 Southampton and rewire the entire dash and engine compartment all in black wire.........!