[scottz70]

I have a 70 Firebird that I am planning a dash wiring harness replacement/upgrade to. I need an upgraded unit that can handle aftermarket electrical items. I am very interested in knowing some things from all of you. The first is what company’s harnesses have you guys/gals installed? Easy? Pain in the butt? Secondly, I am running a flexalite dual fan set up, MSD 6AL ignition box, MSD Pro Billet distributor, and I want to add two electric gauges (oil pressure and water temp), along with an aftermarket stereo and alarm. Are any of you doing something similar in your Goats or Birds? How did you accomplish the extra things?

Here is what I found out so far with my research:

1) Factory Fit: I already bought through Classic Industries their engine harness and front light harness. Apparently they only make a 100% stock glass fuse type dash harness. They currently don’t have and cannot customize an 18 circuit type upgraded harness.
2) Painless: They only make an 18 circuit unit for the 67-69 Birds. Typical.
3) M&H: I contacted them because I’ve heard some good things from members here about them. I called them up and they said that they can make a custom harness based off their existing 70 Firebird harness. They want me to send them the engine and front light harnesses off the car. They want that because they want to integrate the fan ignition power into the light harnesses and add an HEI hookup as well that will run my MSD distributor. They want the engine harness just in case. Does that sound right? Can’t I just get their 18 circuit unit and run the ignition wire to the harnesses? Do the 18 circuit harnesses come with extra ignition and battery plugs/inputs? I forgot to ask that. Last, how do I hookup the MSD box and distributor under this scenario. I currently have the MSD box hooked up to ignition through the firewall and power from the starter.
4) Ron Francis: Don’t make one for that car.

This one is kinda long, sorry guys. Pretty complicated though.

[Ron]

I purchased the wiring harness for my GTO from M&H years ago. They included wiring for my TH400 trans kick down, electric choke, and after market guages at no additional cost....but they were building a complete new harness for me at the time.

Great people!!!!

[azmotorhead]

I Always/Only use M&H
If you want it done right and looking stock/clean. Call & make sure they can add what you want. Then if they can. write down what you would like along with distance measurements of equipment AL6, elec fans, from existing harness breakouts. Add as much detail as you can that way there is no question.send it all to them.

[scottz70]

That helps guys thanks. It looks like I'll go with M&H. Their sales guy was very helpful, taking like fifteen minutes with me knowing the whole time that I was just in the planning process.

Azmotorhead: Thanks for the suggestions on the length of the wires. I didn't think about that. Makes sense. I do have an electric choke, which i'm sure I would have thought about adding to the mix, but forgot to include that initially.

So, it sounds like they will build all the wires that I need into the harness itself running to all my new accessories instead of just adding more IGN and ACC (Battery) terminals to plug these accessories into?

About how long should a wiring harness project like this take? I'm pretty good mechanically and I have the shop space and tools to do this, I'm just a little nervous about pulling the dash apart.

Any suggestions on how to "rattle proof" the dash and everything under it when I put it back together? Dynamat?