Having regretted passing on 1971’s Dirty Harry, John Wayne took a turn in a gritty cop thriller a couple of years later as McQ.

Intended for Steve McQueen, hence the title, the film’s script was heavily rewritten for the 65-year-old Duke.

Like Dirty Harry, it was originally set in Seattle, but the location was changed to San Francisco despite the shoot taking place in Washington state.

The production of McQ, which marks its 51st anniversary this week, almost included a tragedy when a stunt involving the titular character’s rare 1973 Pontiac Firebird Trans-Am 455 Super Duty car went wrong.

The near miss occurred when the stunt driver was preparing to flip the vehicle without ramps.

Stunt driver Hal Needham performed the very first car stunt with a black powder cannon charge. Yet during the second practice run in Los Angeles, the vehicle was accidentally overcharged and the stuntman was almost killed. The stunt performed on the beach in the film was eventually performed by Gary McLarty. Meanwhile, Wayne’s McQ co-star shared just how kind Duke was to her on set.