68 Valiant dies and runs lumpy, then suddenly runs fine.

If it's a points ignition try a new condenser.
Major random changes in how the engine runs is the clue I'm going on without seeing it for myself.

Wow. I actually have a lot of symptoms from all of these! Spraying carb cleaner at the carb base raises idle. Tightened carb down, but didn't see any leakage around throttle shaft. I did get gas about half way through the trip here, which had been almost all highway miles until this point so I wouldn't have noticed the stutters. I'll grab some Heet tomorrow. I also messed with the wire off the condenser while I was remounting the coil, so it could be the culprit too. Might just be the kick in the pants I need to order a pertronix ignition.

You guys are awesome, thank you! It's still running good for the time being, but I'm gonna dig in when I get home tomorrow.