Underhood wiring replacement

[gable74]

So after spending a few days with my new ride I have decided the first project will be to clean up the engine bay wiring. Over the past 40+ years its seen its share of splices and add-ons. This truck was an original T60 and TP2 truck so I would like to track down the correct wiring for those as well. What I am looking for is some suggestions on a good resource for the harnesses. I would like to replace the wiring for everything under the hood all the way back to and including the connector on the firewall. It doesnt have to be NOS stuff or original but at least look period correct. Any suggestions? Phase two will be the mess of wires in the cab.

Thanks,
Jimmie

[Kaptain Kadian]

I ordered mine from classic parts. Fit perfectly and no problems installing them.

[davepl]

My truck is T60 and TP2 and I used the M&H harness. There are several under the hood, the LMC catalog has a great chart for figuring out which is which.

The main underhood harness comprises the back side of the fusebox, is that the one you want?

There's also an engine harness (starter, temp sender, stuff like that I think) and a lighting harness.

The M&H stuff is about the one of the VERY few products during my entire frameoff that met my expectations relative to the original products. Quality stuff - and packed with messy tar (which is good, but messy).

[gable74]

Originally Posted by davepl

My truck is T60 and TP2 and I used the M&H harness. There are several under the hood, the LMC catalog has a great chart for figuring out which is which.

The main underhood harness comprises the back side of the fusebox, is that the one you want?

There's also an engine harness (starter, temp sender, stuff like that I think) and a lighting harness.

The M&H stuff is about the one of the VERY few products during my entire frameoff that met my expectations relative to the original products. Quality stuff - and packed with messy tar (which is good, but messy).

I think the lighting harness was unmolested. There is a main harness AND an engine harness? What does the main harness comprise of? The ones I am seeing listed that include the firewall connector also include the starter, coil, temp and oil sender, etc.in the same harness.

[GASoline71]

M&H or American Autowire. Can't go wrong with either one. Plug and play with all the factory style clips, terminals, tape, channels, and mounts.

Gary

[gable74]

Okay thanks guys.

So it looks like someone has already upgraded the Distributor to an HEI.

I am going to pick up a dual battery harness, an HEI tach harness, and an engine harness. Can someone tell me if thats all I need to get the egine compartment done? The front lighting harness looks to be in good shape.

[snipescastle2]

the factory engine harness, attaches to the front light harness by a "slide connector, what I mean is, the smaller part of the two is the engine harness, that mates to the front light harness connects together before you attach it to the firewall fuse block by way of the through bolt in the harness connector.
the factory engine harnesses also were made for "Points" type ignition, so the provisions will come on the new harness for a "Ballast Resistor", make sure you tell M&H or whomever you go to that makes your engine harness, sets it up for an HEI.....
HTH,
Ben

[gable74]

Not sure what you mean by slide connector. Do you have any pictures of this? I see they make HEI specific engine harnesses, so I got that covered.

[snipescastle2]

The two harnesses actually fit together before you bolt to the firewall...i'll see if I can find a picture....

[Kennuck]

Just a thought. If you plan on updating all your wiring it is much cheaper to buy the complete kit instead of replacing in sections like you are.

[snipescastle2]

Ok, I cant find my engine harness picture, but I believe this will help....if you look at this light harness plug ( the end that bolts to the Firewall side) you'll see a couple of tracks/slides that the engine harness couples together.
After these two are put together, you then bolt it to the firewall side of the fuse block...
Hth,
Ben

[gable74]

Okay, I get it now....Thanks.

So to complete the engine compartment I would need:

Front lighting harness
Engine harness
Dual Battery harness
Tach harness
A/C Harness (optional as that one looks pretty good)

Where does the rear lighting harness plug in?

[davepl]

Here's a map of the harnesses. I'm not going to post the legend because LMC did the work on this so they should get the benefit: check page 160 of their catalog (which you can download online). You can guess the basics, like (3) is the lighing harness, (7) is the transmission harness, (1) is the heater/AC, etc....

[gable74]

Okay I found that diagram on LMC and I can see what I need. Unfortunately I do not see a few components that I want. I do not see:

Engine harness w/ HEI upgrade
Tach harness w/ HEI upgrade
Dual Battery harness

At least I dont think they were there.

[snipescastle2]

I'd check with M&H electrical fabricators on the specialty harness items, at least you will speak to someone who knows these harnesses, and you'll get exactly what you need.
HTH,
Ben

[72 K20]

If you desire you can get a harness that utilizes the later model alternator and does away with the voltage regulator. And you can specify whether it will be mounted on drivers side or passenger side.

Here's a link to an HEI Tach harness
http://www.classicparts.com/1968-72-.../#.VoGT2nlIg5s

Here's a link for an HEI engine harness
http://www.classicparts.com/1970-72-.../#.VoGUJ3lIg5s

[davepl]

I ordered mine set up for HEI and I -think- for a later internal regulator alternator. I know the HEI part for sure, and they sell them through LMC I think. Or find a board vendor that carries M&H, even better.

I decided to still order mine with the TH400 kickdown switch harness even though I don't have the TH400 in there at the moment in case I ever chose to.

[gable74]

Good idea Dave, I like that. So who here is an M&H Vendor?

[GASoline71]

When I replaced my engine harness with one from M&H, it had a new plastic channel and I opted for the addition of an HEI wire. Looks factory.

Gary

[toolboxchev]

I am currently in the process of rebuilding mine, with wire and doing all my own connections.

20 bucks for the wire on the battery alt set up. I am copying some ideas from Mad Electrical for upgrades later. 6 & 8 gauge for this work. I cleaned up all my grounds a while ago and it came to LIFE!

[gable74]

Originally Posted by toolboxchev

I am currently in the process of rebuilding mine, with wire and doing all my own connections.

20 bucks for the wire on the battery alt set up. I am copying some ideas from Mad Electrical for upgrades later. 6 & 8 gauge for this work. I cleaned up all my grounds a while ago and it came to LIFE!

Awesomw. Feel free to post up some info on the process. Wire size and connector info would be great!

Thanks,