Finally making progress on my Challenger this fall. I'll continue working on it through the winter and hoping to hit the tarmac this spring. One aspect of it that needs to be addressed before then is the wiring, so I'm looking for some input on direction.

When decommissioned for rebuilding, the harness had degenerated to the point that it had wire breaks/shorts that made the dash lights intermittent, had killed the function of the turn signals, fuel gauge, and brake lights. So obviously a replacement is in order. However, I'm questioning whether a regular OEM style replacement is where I want to go.

Considerations for this are a few alterations from stock that make me wonder if a universal harness may be better. The car is still going to be street capable but will hitting bracket drags and autocrosses. Things I want to accomplish;

1) Battery in the trunk. This will necessitate a shut off switch and obvious wiring mods. This may also include a Ford style relay to avoid having a large, live wire running the length of the car. In my competition cars, I typically ran everything off the battery and used the alternator to supply the battery. Do I want to do this in a street car or run everything primarily off the alternator?

2) High output 1 wire alternator. This allows bypassing of the factory alternator and regulator wiring and will have more consistent output at idle. Do I want to wire this into the harness or go direct to the battery?

3) Dumping the ammeter for a voltmeter. Dash upgrades will be on the agenda sometime as well. Obviously allows me to avoid the whole bulkhead scorching risk.

4) Future upgrade capable. Aftermarket A/C is in the future for sure, maybe power windows or seats, or electric fans, as well as fuel pump. I don't need heated seats or entertainment systems, but I would like a few extra circuits for future potential.

5)Relocation of some control modules to inside the passenger compartment. Certain things like the MSD box, maybe the coil, methanol injection controls I want under the dash and out of engine heat. Wise decision or no?

6) Headlights on relay system to get more direct voltage.

7)General decluttering of the engine bay. I'd like to eventually hide all wiring so I'm going to need some length for rerouting.

8) I need to retain all original circuits and functions.

I'm inclined to head down the path suggested at MAD Electrical.com but want some input from others who may have headed down this path with past restos or rod builds. If it isn't obvious, this is not a stock restoration focus and functionality and efficiency are at the to of the list.

Thoughts, suggestions, input?

American Auto Wire, Ron Francis, and EZ Wiring all have worthy harnesses.
Avoid Painless

Mad electric has some good approaches. Some of there kits leave a little to be desired, ex: headlight relays.

If you are building the relay kit yourself or looking to buy, I sell part kits with tyco/bosch relays or complete plug and play set ups. No cheapo relays in my stuff. I also do battery cables, alt charge wires, etc.

If you place a cut off switch in the car, might as well wire it so it function in accordance with rules for NHRA.

You have a bit to consider. You'll need a cut off switch with a high rating if you plan to run all those accessories through it.

RE #1 - Aren't you gonna need that 1 large gauge wire to run to the starter motor?

Some people here hate the idea of running a CD relay in the alternator line. I run one all the time when the battery is in the trunk along with a ford starter relay. Throw the kill, nothing outside a 2' cube is hot on my cars. All usually contained in the trunk.

I also carry a jumper, just in case of CD relay failure. I'm no worse off than the guys that run a wire from alt to battery at that point.

Mounts up nice on a plate that holds battery down and keeps everything in one spot.

That's pretty sanitary looking. Nice idea.

Any other input out there?

I went with Ron Francis as I have a custom EFI setup, but honestly it's way better (the Ron Francis) setup than the factory wiring. It's like the Dodge engineers figured out ways to run twice as many wires to do the same thing.

Here is my setup in the glove box:

Relays are for Fuel pump, Injectors, and D-585 Coil packs.

I don't doubt these are all improvements overs stock.

With a quick look at the various sites, it looks like these are the three leading candidates;

Am Auto Wire 51-0289 $729
Ron Francis XP-777 $469
EZ Wiring EZ-21 $185

However, that is a pretty broad price range for what seems to be similar harneses. It does appear the EZ kit will require additional kits added to it, which may bring its price range comparable to the others. Also, American Auto Wire's kit looks like it is darn complete at that price point. I think a call to each of them is in order before I actually buy, but why the big price range?

I re-wired a 57 Chevy with the American kit and was impressed with it. How is the Mopar kit? Last I saw they only made it for E-body.
I build quite a few custom harnesses for hot rods and like the Painless kits, which are a good basis for a custom harness. They aren't really painless unless you understand electrical which I do being retired from the trade.