A then-unknown Sir Elton John sang the Francis Lai and Hal Shaper-penned "From Denver to L.A." as part of the film's soundtrack, which was issued in the U.S. by Viking Records (LPS-105). He was so little-known at that point, that he was credited on the label as "Elton Johns". The label planned to issue the song as a single (VIK-1010, backed with "Warm Summer Rain" by The Barbara Moore Singers), and promotional copies were pressed, but John, who first hit stardom towards the end of 1970, had the record withdrawn before commercial copies could be pressed. Upon his reaching superstar status, promotional copies of the "From Denver to L.A." single have become prized collector's items and an interesting curio in John's recorded catalogue.
Athol Compton was an Australian Aboriginal postman who had never acted before being cast in the film.
To simulate vast crowds of people, thousands of life-sized dummies were placed in the stadium's seats.
Michael Crawford, who plays here a marathon runner, was a heavy smoker at the time of the shooting.
During the marathon sequences, the production crew had many problems with the local police because of the streets heavily occupied by the shooting and the extras crowd blocking the traffic. The other difficulty was the local extras organizations who pulled a racket on the production, demanding to be hired,; if not they would wear pullovers and umbrellas, spoiling a movie supposed to take place in sunny summer moment.