First production to use the new, more sensitive Eastman 4-X film, which eliminated the need for a lot of expensive lighting equipment, especially in nighttime scenes.
Production was temporarily delayed as reported in the 18 November 1964 edition of Daily Variety, after Ann-Margret accidentally struck director Ralph Nelson in the head with an ashtray she was supposed to throw at Alain Delon. The wound reportedly required nineteen stitches to close.
Eddie's car is a 1931 Ford Model A roadster, slightly modified and customized.
Production was delayed several days while the crew waited for cloudy daytime weather to add atmosphere to the big finale. This was just fine with star Ann-Margret. She had been introduced for the second time to future-husband Roger Smith, who was performing in a San Francisco nightclub, and she wasn't looking forward to leaving him.
Ralph Nelson: As a motorcycle policeman and a closeup of feet near the end - according to an article in the 10 December 1964 edition of Daily Variety.