A couple steps forward. Got the car to stay running finally. It was my dumb a$$ fault. I replaced the bulkhead connector on the car and when I was replacing the wires into the new upper connector, I accidentally put the middle upper blue ignition wire in the lower spare position. I was sure I was really careful doing this...apparently no careful enough...lol. Either way, now it runs. I just need to adjust the timing a little and the valves.
Also got the dash lights working again. It was actually a combination of a number of issues. First it was a bad connection at the dash (that was when the shift light was working). Then suddenly it stopped working too. I found i had no power at the fuse block. Checked and found the headlamp switch was working intermittently. I replaced with new. That issue resolved. Then i found the fuse holder was corroded. I sanded the contacts but apparently not enough. Sanded a little more, then I had power again. Shift lights started working and on dash bulb. After a bunch of troubleshooting and sanding contacts, I finally found a bad ground on the other 2 bulbs. The screw for the ground had enough oxidization that it wasn't grounding. A little sanding there and now I have all dash lights working. Also installed my new dimmer and my headlights work as they are supposed to again.
Even got my second horn working again. Tapped it with the wooden handle of my hammer to release the stuck contacts and good to go.
Onto my next issue. I think my voltage regulator is no good. When I first started it, it was bouncing all over. Then it stabilized but just under 12V at idle and only up to 13 when reved up. Pulled the positive off and it stays running but only shows 11.5V on the disconnected positive terminal. The alternator is brand new so hopefully it isn't a dud. I have 2 spare regulators that I can try to see if it changes (once I remember where I put them). I also have a couple spare (not so nice looking) alternators I can throw on if that doesn't work to rule it out.
Fortunately I seem to be checking off more items and issue than I am finding, so I call that progress.