no dash lights

The wire nuts and oddball wires are "quick and dirty" fixes and really should come out to make way for "correct" repairs. Great pictures, though, showed us what you're dealing with. Nothing that any restorer of 40 year old vehicles has not dealt with before, though.

The fuse box could really use a good cleaning on the backside, as well as the front side fuse contacts. The instrument panel needs to come out to give you room to inspect, troubleshoot and repair. You will need a separate ground wire from the circuit board ground to chassis ground, if you run the instrument panel off the factory multi-pin plug (which someone called a "cannon" plug).

I would take the panel out and place it on my workbench, clean all the contacts on the fuse box with ultra-fine wet-or-dry sandpaper, and clean all the contacts of the instrument cluster as a starting point.

ATB BC