I'm working on a friend's 64 Chevelle. The underhood wiring is old, brittle, basically crap. I'm going to install BMW xenon headlamps and a nice audio system, so at first I advised that we should upgrade the battery and charging system. I noticed that the charge wire off the alternator was 10 gauge at best.

My question is, now he wants to redo all of his underhood wiring. If I were to order a forward lamp harness, and an engine harness, would this pretty much cover it? My main concern is the coil and starter wiring, headlamp wiring, and charging system connections. I plan on converting to an internally regulated 100 amp alternator from Powermaster or GM performance.

Any recommended vendors? I see these 12 circuit replacement wire harnesses all over the 'net also, are these typically direct fit or is there dash sheet metal modifications involved?

Call these people: http://www.wiringharness.com They build a very nice reproduction factory harness and they will modify it for the most common upgrades, IE internal reg alternator & HEI distributor. Talk to one of their techs and I'd bet you can come to an agreement on what specifically they can do for you.

I'd contact M&H electric at WWW.wiringharness.com they make a direct plug & play harness that will make your life easy ... also they will modify to run different charging system or dist.. I have nothing but good things to say about dealing with them over the years :) tell em what you're doing & they'll take care of you !!

Awesome, exactly what I had in mind. Thanks guys! Gotta love the 'net...

You may also consider www.factoryfit.com who makes OEM style harnesses.

Note that both of these will be plug in and go harnesses. Both can update them for some of the common upgrades as mentioned. Stuff like HEI and internal regulator alternators.

They will not get you all the way to where you are talking about going though and they WILL be a significant investment. You are talking about a couple of heavy hitters in the headlights and modern wattage stereo components. How much current do these headlights require? How far up the power food chain are you going with the audio components? Do you have relays in your plan?

BTW I have used stereo install kits as a source of high current wiring for alternator feeds.

As far as the headlight current usage, HID's typically require about 20 amps to "fire up" the ballasts, but once they're warmed up they only use about 8 amps. As far as the sound system goes, I estimate a max of maybe 25 amps. I'm probably going to end up building alternator and battery cables myself by cutting cables to length and having the ends attached at Napa auto parts, although I'd like to stay away from sound system wiring since it can't withstand underhood heat and sustained current levels as well as battery cables usually do. I've tried it, and the sheating gets brittle over time.

My main problem is, it's easier to find replacement blade-type fuse panels for 68 and up, but I can't seem to find one for the 64.