PROBLEM WITH IGNITION KEY

Just bought this 69 Dart with slant 6. Cleaned out the fuel lines, etc. Car started but when I released the key it died. I found out after a few tries that the car would run if I kept the key in the far right position (starter).... the starter gear released but car would only run if I kept the key as if I was starting it. My first Mopar since 1970, any clues? Thanks