First, the Year One harness was plug and play for me. I did everything but the dash harness, which is the biggest part I know but everywhere else it was dead on right and easy.
And, Second I recommend everyone should DO the ammeter bypass.
See this article/instruction, it WORKS I did it:
http://www.madelectrical.com/electricaltech/amp-gauges.shtmlIn Mopars of this era all of the car's ammeter charging to the battery goes thru one wire thru the bulkhead connector, to the ammeter and back to the battery. If you get corrosion on the contact surface of the engine wire harness connector or at the firewall bulkhead connector you can burn your car up. What happens is the car pulls the amperage thru the dirty connector even though it is now a point f higher point of resistance due to corrosion. That resistance heats up the connector (very hot) and it will melt the connector and eventually catch fire and you are in world of crap then.
If you keep the connectors like new and apply dielectric grease that is ok and how the factory intended it to work, but our cars are old indeed and you have a lot of energy going thru that ammeter which bothers me anyway. My brand new year one harness almost went up. I caught it when it was just really hot and starting to melt. I decided right then to bypass the ammeter and the bulkhead entirely. I run a big fused wire directly to the battery from the alternator. Ammeter does not work now (I have a voltmeter) but I don't risk my car burning down by the side of the road or worse in the garage and taking it with the car or having the harness melt before I can top it (assuming I have a battery cutoff etc). I would like in the future to put a modified voltmeter in the rally dash ammeter spot, but that's another day's project.
In college in the 80s I watched a 72 or 73 Cuda burn up in a parking lot as my buddies and I could not get inside the car fast enough. In the beginning we were afraid to hurt the hood by prying it open or to bust out the door glass to pop the hood and try to put out the fire (none of us had an extinguisher anyway)...and by the time it was clear that breaking in was the only way to save the car, it was too out of control to matter. We did bust out the glass and try to pop the hood but by then the cable was melted thru. Not sure what caused that fire, might have been electrical but it was frustrating. We did not even wait to see the owner return as the cops and FD showed up.
On another note I have seen several classic cars on fire by the road. Saw one of those expensive Cadillac Eldorado Berlitz convertibles, like a 57 or 58 go up. I mean it burned to just a rust colored skeleton/frame sitting on rims. I think they said a rear brake locked up and caught the wheel/tire on fire.
CARRY AN EXTINGUISHER gents.