When Fonzie wishes it would always be 1955 and falls asleep in the convertible a girl appears and asks him "1955 Chevy"? Fonzie tells her she knows her cars. It's actually a 1953 Chevy.
The convertible was said to be a 1955 Chevy. Way off! 100% 1953 Chevy. Not any other year but that.
The car Fonzie purchases is actually a 1954 Chevrolet (a Bel Air convertible, to be exact), not a 1955 model as stated in the story.
The locomotives approaching Fonzie's car in 1955 is an Amtrak F40PH. Amtrak was not formed until 1971 and the F40PH was not built until 1976.
Fonzie said that Bill Haley did "Rock around the clock" in 1955. Actually Haley has recorded this song first time in 1954.