Regardless of your current problem, you will need a hole in the gas cap. A sixteenth of an inch should be enough.

Many of these cars will drain gas out of the carburetor when shut off. Many of us have installed a shut of valve under the vacuum tank.

Another wild guess: When the engine gets hot, electrical components can break down most notably the induction coil. Like the condenser, the easiest way to check for this is a new coil. Napa carries a 6 volt coil for old VW's which works fine.

Similarly, I had a stalling issue that was solved by running a ground wire from the distributor case to the generator case. This stalling, however, was intermittent.

Vince

Where Are You From? San Francisco Bay Area North

Do You own a car built by Durant? 1925 Star