I had a similar experience last summer. I hopped in my 49' to take it to the Sycamore car show. I made it a mile down the road and it went to hell on me. Spitting and sputtering, backfiring. It would die but start right up and idle rough. As soon as I touched the gas it was stumble and backfire and usually die. I barely limped the mile back home. I noticed air bubbles in the fuel bowl and thought ah ha that's it! replaced the rubber line and clamps from the tank to the steel line. Started up and ran great for a minute or two and went to hell again. Did all of the usual checks, vacuum leaks, timing, ignition, opened up the distributor and reworked the lead inside in case it was the problem. Every time I started it it would run great for a minute or two.
So I changed the points. Ran great, took it down the road and barely made it mile and it started all over again. Barely made it back again. Culprit was the condensor.
When I got my first everyday car (actual first car was
a 1935 Buick bought in 1970) and second car, my dad
put in the glove boxes a new set of points and condenser
and the few tools needed to change them.
"In case you get stuck" He also said never change the
points or a condenser without changing the other one.
Jeffrey
