The Stovebolt Site Forums The Shop Area The Electrical Bay Wiring Harness for engine swap truck

Our 51 GMC 100 was purchased with recent swap out of the stock 6 to a 350V8. The original wiring harness was severed, only power necessary to start engine is currently wired. I plan to keep it very basic, only gauges, turn signals, headlights etc need rewiring. Current wiring was cut at each lighting assembly. I did find the fuel sending unit wiring behind the seat.

I am considering purchasing a 12 circuit Speedway Motors wiring harness. I am keeping a tight budget as I plan on changing out the front axle for a complete IFS.

What is the most user friendly, economical way to go?

Thanks!

I've kinda always just made my own looms and did so on my '51 Burb. Got a marine fuse panel and went to town. Having said that, I found a really neat electrical system company. I pulled the trigger on their roadster wire kit for my Model A. Really top notch stuff. I found their pricing reasonable, compared to some of these other more well known companies.

Coach Controls

When I did my first full vehicle harness, I discovered that I could buy a 200' spool of each of the colors I needed and a fuse block for the price of one of the wiring kits. Now 4-5 vehicles later I still have some of that wire.

If you are planning to do more than one, I would recommend buying bulk wire (I get mine from Waytek) and making it yourself. If you are only ever going to do this one truck, then the added labor might not be worth having the extra wire.

I also like doing it myself so I can route everything exactly where I want it and have every wire be exactly the right length.

To add to that, I'll cheat a little sometimes and go get some bundled trailer wire. You can go 5 wire or 7. Great for running from the front of the vehicle to the tail lights. Already wrapped up in a cover. Like this stuff.

You are choosing the right harness and the right path for an economy and dependable re-wire. For show trucks we make our own harnesses with each wire parallel, matching bends, and terminals both crimped and soldered. A complete waste of time for your goal. Go with the Speedway 12 circuit and be driving the old Jimmy while the perfectionists are just showing pictures of their half done projects to their light beer drinking buddies.

Those 2 things often do not go together. Going on the assumption that you want an "off the shelf" solution, I would agree with Coilover that the Speedway units are a good choice.

I have used the painless brand and found them much more expensive than Speedway, but not really any nicer.

I also bought a couple of the super cheap ebay ones out of morbid curiousity. They were bad enough that I gave them to my daughter to make fairy houses.

That said, for as little as it sounds like you actually want wired up, you could wire it by hand in a day for under $100.

Thanks Mark for both of those links. Love the Coach products and the trailer wire link. Can the 14 gauge trailer wire be used for the entire rewire?

Evan,
Thanks for your insight, this is my first project, and I’m trying to keep it fun, low budget, with an eye toward increased engine performance.

Fibonacci,
Thanks as well, you guys make wrenching, and crimping fun and within reach of mere mortals…

I've only used it to go from front to tail lights, but I suppose you could.

Not all of the wiring is 14 gauge and you would not get the benefit of color coded wiring. Spools of stranded copper wire are really expensive right now and it may just be cheaper to buy the kit.

I replaced most of the wiring on my truck (not all the same time), with off the shelf black and red wire, several boxes of crimp connections and several trips to FLAPS ended up spending more than a harness would have cost. Although my wiring is now good, I don’t have the benefit of color coding.

If it was me, I would bite the bullet and buy a kit, its straight forward and quicker, as you would not have to make every crimp/solder joint and you’ll have instructions on how to do it.

Phil is correct, although they do make some that are 14 gauge only. The reason why this wire is more ideal for going to the rear, is that it is color coded correctly for lighting. Yellow - left turn, green = right turn, blue for electric brake, etc. The benefit here would be, if/when you wanted to set up for towing, all the correct color coded wiring would be at the back of your truck and you could connect to a multitude of trailer configurations. But, if you were to take this cable and try to strip off the jacket to just use the wires, the labor wouldn't be worth it.