In Reply to: stumbling 8n posted by Jakester on July 25, 2018 at 11:33:16:
How long has it been since wire terminals were cleaned? This is not as much of a problem with a 12 volt system, but can still eventually become a problem. This is especially true while cranking. Available battery voltage is lower while cranking. Both ends of both battery cables clean and shiny. Make all terminals in the ignition circuit clean and shiny. Replace the ignition switch.
When replacing the distributor, was the timing set right? I've got two distributors that I had to file the screw slot in the housing longer, so the plate would move far enough to set the timing. Once the timing is right, the special brass screw that makes contact with the coiled springy terminal is now offset to one side. I have to bend the coiled springy terminal to that side.
Slow to start may also be caused by poor compression. The older the engine gets, the longer it seems to take to get cylinders to fire. Using more choke may help with that, but a rebuild is not far off. Removing a spark plug removes the compression load of one cylinder. Faster cranking equals higher compression, making the other cylinders easier to start.
When was the air filter last completely cleaned out? I've seen those so clogged the engine shouldn't have been able to get enough air thru them.