1936 Packard 120 Convertible.
From what I found General Motors Motorama was a GM Auto show. Not an actual vehicle. But a show to show off concept cars and prototypes. I have no clue what the vehicle pictured is.
Edit: The one in the background I think is a 1955 Buick Wildcat concept car
The one in the foreground looks like a 1954 Olds F88 concept