The brainchild of senior Ford executive Lee Iaccoca, the Ford Mustang quickly became the fastest selling car of all time on its release in 1964. Alan Mann Racing was sent a preproduction chassis in February 1964 for testing and evaluation before homologation. The car was tested secretly at Goodwood and a detailed report was sent back to Dearborn. Ford had decided to enter the Mustang in some European endurance rallies, including the Tour de France and Marathon de la Route. AMR prepared and entered the cars, and won the Tour de France, providing the new Mustang with its first competition success worldwide. AMR also prepared a Mustang for Roy Pierpoint which won the 1965 British Saloon Car Championship, and the convertible for the Bond film Goldfinger.

Alan Mann was personally very fond of the Mustang, and on his return to racing in 2004, it was a Mustang he chose to relaunch the team. AMR still runs a Mustang in historic races today, which was built by Brian Lewis who worked on the Alan Mann Racing Mustangs in 1964.