The poster indicates the movie is set in 1957 but the year is given as 1958 onscreen.
Daniel is killed in the opening scene, set in 1932. When the family visits his grave, the headstone gives 1934 as his death year.
After they rob the bike track they escape in a 1960 Edsel, but the movie is set in 1958.
When Melba is first escaping the zoo she's driving what might be a mid-1950s Packard, but she runs the roadblock in a 1956 Pontiac.
Incorrect - Melba is shown crashing the 1956 Packard, then escaping in the 1956 Pontiac (which was earlier shown as Bertha's car).
In the parade scene prior to the bank robbery, a Radio Shack logo is visible on an outside wall. The scene takes place in 1958 but the logo featured was only in use from 1971 through 1994.