64 Dart with 273 4-speed Carb

What is a good carb to use on my friends 64 Dart with a 273 4-speed. It has a Edelbrock 1406 2166 on it. Sometimes it runs good and sometimes after driving it and you come to a stop it cuts off, will not idle correctly. Starts back up and then runs rough for a little while. Idle set at 700-750 any ideas on the 4bbl.