I have just finished parting out my 3800 donor, and have a lot of excess wire saved. Took all of the harnesses I could, and have started stripping it down. I was trying to come up with a way to store, and then access the wire. Looked on the net, but couldn't find anything, but then the light bulb clicked on and I had an idea. Use Screen Door springs!
I used some scrap lumber I had laying around, about 3' long. You can add as many "layers" as you like- I started with 2. The springs I got at Lowes. They are Stanley Screen door springs, #4. They also have a #6 that is a bit larger diameter, but I think it would be harder to use.
Attach one end of the spring to the board. Then you need to stretch the spring to at least 30". Be careful- this can be dangerous. I used a wire tie formed into a loop, and then used a clamp to slowly stretch the spring. When I had it where I thought I wanted to be, I used a second clamp directly on top of the spring to tightly clamp it to the board. I then released the first clamp, and fastened the end of the spring with a screw. I placed screws every 8" underneath the spring, to help keep the spring from sagging under the weight of the wires attached.
For larger gauge wires, I used a "softer" spring I had laying around. It was an old Carb Return spring, but you get the idea.
For me, I set a parameter of longer wires in the upper spring, shorter wires in the lower spring. Might work better if reversed, with the long wires on the back. The longer wires were coiled up and the ends dropped into a cardboard box. A trash barrel would work good too.
Using the wire is easy- just pull on it and it comes out. Some of the wires I saved had the terminals still on the ends. These I installed into the spring with the terminal visible for easy identification, should I need a wire with terminal.
I mounted mine on the end of a shelf. I have 12" ceilings, so I installed a long board on the end of the shelf with a pulley at the top. I can then winch up the collection out of the way, or let it down for access. I used a clip on the end of the cable so I can remove the whole collection from the pulley. Useful when you want to add more wires, or for general use. It could easily be mounted on a wall. If you have a workbench where you do electrical work, it could be mounted on the wall in front of you, with the wires falling down behind the bench. I'm sure there are other ideas.....
I'm sure that this idea can be improved upon. I just offer up what I've done so far, and look forward to hearing how to make it better.
'87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) T460e.