[Berg]

Don't overlook the choke pull-off if so equipped. The pull-off will open he choke enough to get air to keep the car from stalling. If this isn't operational you will have problems similar to the choke not being set correctly like you describe. They are usually around $20 for a replacement. I'm going to assume you have a Quadrajet although it could be a Holley or Edelbrock/Carter or any of the above. If you still have points I recommend checking/replacing the points, condenser. If it is HEI it probably won't be the problem but I can see weak spark giving you a hard time on start up also.