Thanks for all the suggestions!

The jeep has been upgraded to 12v, so I ordered a new Borg/Warner coil
from http://www.willysjeepparts.com/ . I also have a new condenser and
points from when I got the tune-up kit and replaced the distributor cap
a few months ago.

I should be able to install the three parts in a couple of weeks and
I'll report back if it did the trick....