I have owned a 69 Barracuda for over 30 years. I have restored it twice. The wiring was in pretty good shape. But I wanted the wiring under the hood to look really nice, so I bought the appropriate harnesses for under the hood. I bought new, reproduction harnesses from Year One that were made by a company called M&H. The wiring is BEAUTIFUL. Exact replications of the originals in every way. Then I laid out all the rest of the wire harnesses and CAREFULLY inspected them to include using a multi meter to check continuity of all wires. I found only a few fairly minor problems. I fixed them with solder, heat shrink and/or or electrical tape, then I reused the harnesses. I did NOT use any of those crimp style connectors! I have never had a problem with it. If your wiring is usable, and you wanted to reuse some of it, you might be able to do the same level of inspecting and repair that I did. That being said, you could buy all new wiring, but it will cost you over a thousand dollars front to back. Yes, it would be a good safety step. However, I think that if people CAREFULLY inspect/repair their wiring, it can often be reused. Unless you are really good with automobile electrics, I would stay clear of the less expensive generic harnesses. Also, buy a good wiring diagram! Here is a link to the M&H harnesses at Year One. Yes, they are expensive; and Year one charges dearly for shipping, but if you get on their email list, they send out 20-25% off coupons all the time.
A-Body 1962-76 - Dart - Duster - Valiant -- Electrical / Harness / (yearone.com)
