shifting shuts my car off

Saw from another post that it is a slant 6. 1 or 2 bbl carb? It sounds like you need to rebuild/replace that carb or hunt down a vaccume leak. Set your bast timing and then adjust your carb and see what that does. Picking up a few cans of carb cleanner and spraying the hell out of the carb wouldn't hurt either. Can you post a pic of the engine bay?