Max Frost (Christopher Jones) asks Billy Cage (Kevin Coughlin) how long he thinks he is going to live and he replies, "Thirty, man." Coughlin was killed in a hit-and-run accident on January 19, 1976, only five weeks after his 30th birthday.
According to Larry Bishop, Richard Pryor pulled a prank in which he came to the set naked and shocked Shelley Winters.
The song "Shape of Things to Come", written by Barry Mann and Cynthia Weil, was a number 22 chart hit for Max Frost and the Troopers (a "studio group" made up of session musicians) in 1968. In 2006, it was featured in commercials for the Target Corporation.
American International Pictures originally offered the role of Max Frost in the film to noted folk singer-songwriter Phil Ochs, who was known at the time to want to branch out into film work; however, after reading the screenplay, Ochs turned it down, saying that the story presented the youth counterculture of the 1960s in a badly distorted light.
Lowering the voting age in the U.S. from 21 to 18 was a real political issue at the time of the making of this film, particularly during the era of the Vietnam War, when young men between 18 and 20 were being drafted into the military, but could not vote. It came to pass with the ratification of the 26th Amendment to the U.S. Constitution on July 1, 1971.