According to Jeff Bridges the gunfight in the forest had to be completely re shot after the film was ruined in the lab.
The classic rock band Bad Company named itself after this film. When Paul Rodgers (ex-Free) formed a band with Mick Ralphs (ex Mott the Hoople) in 1973, the first public warm up gigs were in Germany. Just prior to the gig they saw the film. When asked what the band was called, they remembered the poster, and adopted the name.
Twenty-six years after this movie was released, Jeff Bridges (Jake Rumsey) and David Huddleston (Big Joe) appeared together again as The Dude and Big Lebowski.
David Newman and Robert Benton both readily confirmed that the character of Big Joe, played by David Huddleston, was based on a real person, the film director Joseph L. Mankiewicz; his famous line about being "the oldest whore on the block" derives from a joke often made by Mankiewicz about himself.