[jeepguy1948]

The “Old Guy @ 94 years old” say’s “most carburetor problems are distributor in nature”. I can’t say what might or might not be wrong with your distributor but I would think that if it behaved the same way with 2 carbs that’s not the problem. Most all intake vacuum leaks on a Model A motor are so small that propane does not work as a diagnostic tool. Since you “gave up” perhaps you can find another Model A owner that can test your parts on his motor (a good reason to belong to a club).Personally, I would like to own at least 2 Model A’s myself so I can test my own parts but alas, I have neither the space or the cash to do so.