One of those products you really can't live without in your 80 is a Wits' End Quarter Panel Mount. This kit is meant to make it that much easier to keep your wiring back there clean, tidy, and secured.
Our kit includes:
-2 each of the top (horizontal) wire chases
-2 each of the vertical wire chases (along with appropriate wood screws for mounting to panel)
The TOP chases follows the angle between the wood panel and top flange to maximize utilized space. It also easily mounts with the hardware that attaches the wood panel to the metal frame. NO holes to drill/screw/etc.
The VERTICAL chases are an optional install (but always included in the kit) with the included wood screws. This will keep any and all of the wires running down to the bottom of the fender well, air compressor, etc secured as well. One in the middle and one at the back is how we usually end up running them, but that choice is yours.