A few years ago we took a car totally apart and learned a lot about wiring in the process. Novices tend to think of automotive electricals as a few single positive and negative wires running here and there with fuses in between. Well, think again. By the time we got our car stripped down, we had a taped up bundle of wires that wouldn't fit into the cardboard box we planned to store it in. There were several separate sub-harnesses and probably hundreds of different junction boxes, plugs, terminals and connectors, plus clips, cables, relays and switches.
For those building '40s and '50s Resto-Mods, American Auto Wire offers its Highway 15 Nostalgia series wiring kits with braided wiring and Mega fuses.
A company called American Autowire that we'll introduce you to in awhile, makes 9,000 individual parts for vintage GM, Mustang and hot rod and custom wiring systems. American Autowire says it has the ability to make 50,000-60,000 wiring harness combinations for just GM cars.
That gives you a pretty good idea of how the "universe" of electrical wiring products is. However, everything eventually has to filtered down to the one car you're building into a Resto-Mod, with all of its factory features and aftermarket equipment. And then, you need the parts you buy to give you fault-free lights, sound, charging, ignition, etc. Don't panic. The companies that make harnesses and other electrical parts are making it easy as possible for you to wire up a car.
When Jeff Noll first got his '67 Camaro, it was a little difficult to figure out the electricals, since the coupe was not a running and driving car when he bought it. He wasn't positive if all the wiring under the dashboard in the car was factory correct or not under the dash. Fortunately, things worked out in the end.
Since Jeff was converting the car to the Rally Sport appearance, he did have had to purchase a new front wiring harness. It came from Classic Industries and had all the connections for the HEI distributor, tachometer, gauge sensors and for relays for the electric RS headlights. Though the Classic Industry front harness was correct, Jeff discovered that the RS dash harness also had distinctions. The wiring connections under the dash were different. This made the conversion a bit challenging, because once the new front harness was plugged into the firewall, additional under-dash changes had to be made. As we'll see in awhile, situations like this aren't an uncommon occurrence.
In his '69 GTO, Jim Mokwa used an aftermarket wire harness from M & H Electric Fabricators and found it to be a very good reproduction. M & H manufactures a complete line of exact reproduction wiring harnesses, battery cables and switches for Classic GM, Chrysler and AMC muscle cars. Jim received very good technical help from M & H during his install.
M & H Electric Fabricators hand assembles harnesses to OEM specs to ensure a perfect match of gauge, length, color and tape. The company also offers a kit to convert 1963 to 1972 GM vehicles with an externally-regulated alternator to use an internally-regulated alternator system. This conversion is easy to do. First, you disconnect your external voltage regulator leads and plug the M & H regulator adapter into the regulator lead wires. Then, you disconnect your alternator lead wires. Install the new GM internally-regulated alternator. Finally, plug the special $19 alternator adapter into the alternator lead wires.
M & H also has a $15 harness modification that converts a 1955-1974 GM breaker point Ignition system into an electronic High Energy Ignition (HEI) system. They add the proper wires to the original type harness and leave out unnecessary wires. The new harness will still have a factory appearance, too. The install is easy, with a single wire going to the HEI distributor cap for power.
As we said, American Autowire and other electrical wiring suppliers try to make it as easy as possible for you to get the wiring harness you need to fire your spark plugs and light up the road ahead of you. During an informative seminar at the Hot Rod & Restoration Show, company reps pointed out how they have developed Factory Fit products for 23 stock GM marques or nameplates, Classic Update kits for mildly modified cars and a variety of universal kits for any car. Some Resto-Mod projects can get by fine with the vehicle-specific offerings, while other cars with many modifications can still be wired up relatively simply with the Highway Series, Builder Series or Power Plus Series universal kits.