Please see the attached vacuum diagrams. I redid my vacuum routing and vent for a test drive and it almost didn't stall. Almost would be the key though.

The only thing wrong now is the distributor advance does not hold vacuum. Could that be causing it. The advance unit bottom hose is what's not holding the vacuum, the top one holds it just fine.

Anyway the only way I can stall this thing is by cruising at 1400 rpms and dropping the gas pedal. Half the time it starts itself back up but the other times it does not. What do you think could be causing that problem?
It almost feels like whatever lets the rpms drop down gently does not work. On the modern cars I've replaced the idle solenoid to fix the problem.

Dmitri