Dash
That is the only thing keeping me from messing with my dash lights, the cable. I have read so many stories on hear of speedo cable issues after removing the cluster that I have not taken that one on. I need to, I only have one or two dash light working and my headlight indicator does not work, so at some point if one more dash light burns out I will need to bit the bullet and do it so I can see the dash at night.
I did the brown wire conversion on my 79 and replaced all the lights with LED except the blinkers (they sent me the wrong digital flasher). It made a big difference in my voltage. Before it would drop way down with all lights and wipers on at night, and when you hit the blinkers with the wipers on it would dim everything, now she stays right at 12 volts all the time, lights are brighter. Was a great upgrade. If you have not done the brown wire conversion yet you should look into it, when I got to the ignition switch it was burnt and crispy (which is a common issue the way these cars where wired with only one 10AWG wire from the battery to feed all the electrical in the car) so it needed the upgrade before something bad happened under there.
Going to do the simplier brown wire and terminal upgrade and add all LEDs to my 86 when I put it back together after paint this spring to bump voltage supply and avoid future issues.
Good luck.
PW