Is is possible to custom build a wiring harness for a customized car? I could buy an original wiring harness, but would have to modify it. Rather than modify an original harness, it may be better to start with a blank page.

So my questions, Is this a practical idea? Where would I find quality wiring components? Are the plastic ends available which plug onto various components on the car such as the transmission, electrical motors, etc.

it depends.

if you mean for the whole car end to end, I am not sure if it is worth it.
expense wise, there are plenty of kits out there that you can modify to your hearts desire that are cheaper than you can build it yourself.

if you mean something like an engine harness or tail light harness, then sure. I wouldn't bother to use factory ends unless I need them, and then I would just take apart the original and make new ends using those connectors. for the rest I would use weather pac connectors.

I rebuilt my own tail light harness doing that and using new tail light ends.
BUT I only had to deal with 4 colors of wires.

An under dash harness is probably 15 or so colors with and without tracers.
Can be done, and honestly could be simplified quite a bit with a few relay's etc.. but would be expensive due to the sheer number of spools of wire required.

the common ends are available at napa, but you have to take appart the plastic part of the connectors to reuse them.
some simple tools allow you to do it pretty easy.

If it were a completly custom car, then you really don't have a choice but to wire your own. But you would be better off not to limit yourself to the stock connectors unless you have to plug into something factory as chrysler is a pain about allowing someone to make the correct connectors.
that is why most aftermarket universal wiring harnesses use GM stuff.

Personally, I like making my own harnesses...I like being able to custom tailor to suit my needs, resulting in no unnessary wiring and a neater appearance. You can find good weather sealed harness plugs on eBay for cheap, and you can buy wire in larger quantities on eBay and have more than enough....just my preference though.

Hybrid is a better approach. Try a kit that has all the circuits you need plus a couple extra and then make all the new ends or tap into factory lighting harnesses. I used Kwikwire, they are like $300.00. It still ends up being quite custom. I know my car wouldn't be stick, the battery was going in the trunk with a relay, I was installing an under hood relay/fuse box for lights and HD accessories, radio was going in the glove box, MSD and coil in the car etc... http://www.kwikwire.com/wh_22Circuitstreetrodwiring.html

I wired my A-100 from scratch using quality wires and modernized components. I would suggest against doing it, because of the cost. Get a good kit with GXL wires and good fuse block, and modify it.

Good luck,
Ran

I just did my 64. The only OE part I used was the right to left tail lamp harness. Built the engine harness in my Challenger as well.
Doug

dash

better trunk

Firewall from the back and thru the frame rail out front

dvw, WOW! that is very nice work! I'm embarrassed to show my wiring now! I did a ProStreet Camaro wiring from scratch, well sort of. I used an "Enos" (enoscustom.com) panel and wired the rest myself. Might want to check that out. Very easy to do and very nice instructions too. Take care, Jeff