I have a 72 Demon I am looking into rewiring. I am also debating if I will attempt it myself or hire it done. I am looking at the 22 circuit universal harness from Speedway, the similar universal harness from Painless, and the Mopar coded Painless harness. I currently have the Speedway harness in my 64 f100. 10 years and no issues but I did not install it. I am also swapping over to MSD ignition, adding an electric fan(s), have an electric fuel pump, plane on a decent stereo, Autometer gauges, and I have eliminated the heater box.
Any input from those that have done their Mopar?
What is a good location for the MSD box?
Having thought about this for a day, I have a question for the OP.
Exactly
why do you want to rewire your car? Are you having issues with the stock harness? Is it otherwise damaged? Parts of it missing?
Re-reading your original post, that could govern the OP's need to consider my next suggestion:
If your existing harness is generally in good shape and you're just wanting to modernize or accessorize, consider adding a remote fuse panel, similar to late models. This can be ripped from any car you choose in the salvage yard, as most of them are readily accessible, have a ton of readily available fuses, and are easy to pirate. Then you have a plethora of new circuits you can add, and most of the new fuse boxes only require running two wires, for power source and ground to get you energized. Further, they are also well-equipped with
relays, which are your best friend when adding accessories and can help fire-protect your ride.
Neon and Charger underhood fuse panels are great for this. Relabel the lid of the fuse box and you're golden. Electric fuel pump? The fuse and relay are already labeled, wired, fused, and relayed. Supply power, hook 'er up, done. Power windows? Same. Ignition? Same. Dixie horns? Same. This saves you the effort of re-wiring the car, and offers the ability to
keep the factory diagrams which will save your butt at some point in the future (You
do keep a laminated copy of your car's diagram, with all additional mods and circuits, in the trunk or glove box, right?). Trying to trouble shoot aftermarket harnii can be a real *****, especially after a few years have gone by, and then if it's all re-wired very few people here can help you at that point...whereas with a stock harness, some people on this site can tell you what that green pigtail under the hood is, just by description.
Then the only other mods the OP requires are
possibly a larger alternator, and the regular upgrades like bypassing the troublesome bulkhead connector, ammeter delete, election interference in Pennsylvania, etc.
Based on the 3 or 4 things you suggested you want to modify electrically on your Demon, I would
not rewire the car. If something is wrong with it electrically now, I
might suggest replacing the factory harness before you modify this stuff, but that really isn't that difficult (not that it's easy mind you, but there's a process), but that depends on what's wrong.
Besides, adding a secondary fuse/circuit panel lets you revert the car to stock much more easily should you decide to restore, sell, or further modify in the future. I think it's safe to say that most of us add that stuff when we're young, then regret adding at least some of it when we're older! For example: when I was 16, the dipstick behind the counter at O'reilly's told me that when the fuse blows, you're just supposed to install a bigger fuse. Yeah, no. Not the hot upgraydd. Well, it did
get hot.
When selling, most people want something unmolested, so this can protect your investment and keep options open for the next owner.
Plus, it's less work!
