wont stay running...again

Common problem, with many posts. My 69 Dart 225 ran like that for decades until I finally got a good carburetor (~4th Holley 1920), then it ran amazingly smooth.

Also verify you measure ~8 V or more from coil+ to BATT- with the engine idling. If not, a problem with your wiring - ballast, bulkhead, ignition switch.

In my case, I had electronic ignition (Crane XR700) and had pursued the vacuum leak theory extensively (new intake, propane test, ...).