[Badgoat64]

We have a 64 GTO that needs to be rewired. I’m looking for suggestions on what brand of wiring kit to buy. I have a mixture of stock parts and mods that have been done to the car. The engine is a 461 stroker, it has an electric radiator fan, electric fuel pump, air conditioning, and bigger alternator. I want to make sure I have expansion space available for possible EFI and a decent sound system in the future.

I talked to Painless, and they do not offer a kit specific for a 64 GTO. They recommended their 23 circuit GM muscle car kit, part #10402.

I’m leaning toward this Painless kit at the moment. Has anyone bought and installed a kit that they recommend?

[JSchmitz]

I put the American Autowire Classic Update kit in my '64 GTO. I was really pleased with the quality and instructions. I bought the large and small crimpers too. The crimpers are a must have!

[Badgoat64]

Originally Posted by JSchmitz

I put the American Autowire Classic Update kit in my '64 GTO. I was really pleased with the quality and instructions. I bought the large and small crimpers too. The crimpers are a must have!

Thanks for that info. This actually looks really good. How long did it take to complete? With this kit, is there extra space for accessories?

[Chris65LeMans]

M&H. It's an exact replica of the current harness, so it makes swapping 'em out easier. They have great customer service, too - call 'em up and ask about your expansion questions - I'm sure they have a solution for that.

[HoovDaddy]

I used American Autowire Classic Update in both cars. It's the best of both worlds, you can do stock or it has built in options for aftermarket parts (electric fan, fuel pump, factory or aftermarket gauges, electric speedo, different ignition systems, different charging sys). Comes with everything you need. The wiring feeds are extra long so you can route them any way you want, that said, you have to terminate every connection either crimp or solder. I've used Painless in the past which is okay for pure stock, but I like AAW better because I'm not a purist. AAW Classic kit will take longer that the stock type replacements because you have to attach all the terminal ends.

[ZeGermanHam]

Another vote for American Autowire Classic Update kit. I used it on my '66 and it's great. I rewired my entire car, having never done auto wiring in my life before, and everything worked perfectly the first time. Love the updated features of the Classic Update kit as well. Another thing that makes it nice is that, unlike the stock wiring setup, it has an upgraded headlight switch and dimmer switch that allows the headlights to get more voltage, which translates to brighter headlights and better nighttime visibility. There's a number of good reasons to go with the Classic Update kit if you are concerned with being 100% original.

[JSchmitz]

Originally Posted by Badgoat64

Thanks for that info. This actually looks really good. How long did it take to complete? With this kit, is there extra space for accessories?

You're welcome. I don't have a good estimate on completion time. I did it a little at a time over months. It has lots of extra circuits vs. stock. At least for my car it did. I do have a sub panel for LS swap relays and fuses.

[drewm]

For those of you that used the classic update instead of the M&H harness and had to cut their firewall for the larger fuse panel, how does it look? Is the cut out part obvious or does it look OK? Is the switch to modern fuses worth it? My car is completely gutted and I could go either way, but I have no plans to change to HEI or anything, so I am not sure if the upgrade is worthwhile.

[Scarebird]

Originally Posted by drewm

For those of you that used the classic update instead of the M&H harness and had to cut their firewall for the larger fuse panel, how does it look? Is the cut out part obvious or does it look OK? Is the switch to modern fuses worth it? My car is completely gutted and I could go either way, but I have no plans to change to HEI or anything, so I am not sure if the upgrade is worthwhile.

Yes, very much so.

[JSchmitz]

Originally Posted by drewm

For those of you that used the classic update instead of the M&H harness and had to cut their firewall for the larger fuse panel, how does it look? Is the cut out part obvious or does it look OK? Is the switch to modern fuses worth it? My car is completely gutted and I could go either way, but I have no plans to change to HEI or anything, so I am not sure if the upgrade is worthwhile.

I only had to cut a small part out. Looks fine to me.

[drewm]

Originally Posted by Scarebird

Yes, very much so.

One more thing. I am a bit colorblind. I have no problem with electrical work, but sometimes with so many wires bunched up, it get a little confusing. I believe the M&H wires are labeled (as well as the correct color). Do you know if the AAW upgrade is also labeled or just color coded?

Thanks!

[Scarebird]

IIRC the plugs are labeled, not the wires.

[ZeGermanHam]

Originally Posted by drewm

For those of you that used the classic update instead of the M&H harness and had to cut their firewall for the larger fuse panel, how does it look? Is the cut out part obvious or does it look OK? Is the switch to modern fuses worth it? My car is completely gutted and I could go either way, but I have no plans to change to HEI or anything, so I am not sure if the upgrade is worthwhile.

It's 100% worth it, in my opinion. Here are some photos of my car showing how I expanded the opening for the fuse block. With the car fully assembled, it looks like it could be OEM if you didn't know any better. It's fairly buried under the brake booster anyway.

Originally Posted by drewm

One more thing. I am a bit colorblind. I have no problem with electrical work, but sometimes with so many wires bunched up, it get a little confusing. I believe the M&H wires are labeled (as well as the correct color). Do you know if the AAW upgrade is also labeled or just color coded?

Thanks!

At least on the AAW Classic Update kit, the wires are both color coded AND labeled with identifying text. You can see some of the text on the wires in my photo above. It could not be any easier. The kit is not pre-terminated with the plugs, so you will have to route & bundle everything, then terminate w/plug. This is preferred over pre-terminated wiring, IMO, as you can make adjustments and improvements with wire routing.

[giles]

Originally Posted by Chris65LeMans

M&H. It's an exact replica of the current harness, so it makes swapping 'em out easier. They have great customer service, too - call 'em up and ask about your expansion questions - I'm sure they have a solution for that.

I’ll second the quality of M&H for a very correct original harness. I used them for complete set of harnesses on my ‘64 and installed dash, engine and forward lamp harness in a friend’s ‘65. Perfect replacement for an OE harness.

[Gator67]

I used M&H for three factory appearing "correct" cars. Looked great and functioned perfectly, but I didn't add/change any circuits to these cars. I used AAW classic update kits on two pro-touring style cars (both second gen Firebirds)...lots of flexibility with new circuits I needed, and although I had never done this type of wiring before, it was easy once I gained confidence...I just took my time and triple checked everything I did. As an aside, I found that GT150 and Weatherpack style connectors are useful when adding/modifying circuits for efi, fans, A/C, sound system, fuel system, hidden wipers, etc.

[rolling money pits]

Curious, I have AAW harnesses for engine and forward lamps…will the classic update dash harness play nice with them?

69 with hideaways…

[HWYSTR455]

Not sure if the forward lamp and engine harnesses plug into the AAW Update fuse block but suspect they do. I will have to look at mine.

I've done one car and am most of the way done with the 2nd car, but it's in paint jail at the moment.

One thing I noted on the AAW Classic Update harness for my 70 (a-body) was that the bulb sockets were not sealed, either potted nor rubber seals. I had a new rear light harness from M&H and it plugged into the AAW harness so I used that. Believe I did the forward light harness too but I may have just swapped the sockets.

I guess you could glob RTV to seal them up but I thought that would be unsightly.

My engine harness I completely fabricated using the one provided in the AAW kit as a basis. I broke out sensors, ignition, and power/charge in to separate harnesses.

I used split mesh/braided sleeving on everything, too. That adds to time, but in the end, it was well worth the effort. I also broke out some dash sections into sub-harnesses using metri-pack connectors. That too added time/effort. Again, was well worth it. If I need to mod or change anything, I can limit it to a sub-harness, as an example.

The power feeds thru the firewall into the compartment are beefy, and even have extra sources for add-on accessories, like aftermarket AC, etc.

Another thing to note is that the front to rear intermediate harness is not wrapped, and they don't provide any type under carpet protector. They do have a 'universal' one you can buy, but it's not very good, so suggest re-using the OE one.

.