A few thoughts.
A majority of the time stall at stops are carb issues.
Make sure all passages are thoroughly cleaned, including using a paper clip. Spraying and compressed airr sometimes are not enough.
Have you tried a known good carb? something that runs properly on a different car.
Typically for this issue you lower the float level in stages up to a float level guage reading to as much as 15/16ths.
Here is some additional carb info,
https://www.model-a.org/
If rebuilding your own carb, try flow tested jets from Renners Corner.
http://www.rennerscorner.com/carburetor.html
Also Berts has an excellent reputation for rebuilt carbs, but the wait time can be long.
Are you running wireless distributor plates? They can do some odd things, including your symptoms.