64 Plymouth 273 Intermitent severe misfire.

Condensers will do some wacky things like that. Still have points? Also, the new condensers are junk. Get a hold of Halifaxhops for a old stock one.
Hey man, guess what??? It was the condenser!!! Thanks. I've put a couple hundred miles on it and it hasn't skipped a beat. I even ran the tank down to 1/8th. It's just a real nice cruiser now. Wahoo!!!