I think it was a 1950 Chevy convertible that Herman Munster bought for his niece Marilyn, purchased from Fair Deal Dan (We're Here To Stay), and then the car stalls on his way home, and then later falls apart in front of his family..
IMDB is the source for TV and movie car links http://www.imcdb.org/vehicle_262831-Chevrolet-Styleline-De-Luxe-2134-1951.html