Offenhauser was an American engine design that dominated American open wheel racing for more than 50 years and is still popular among vintage sprint and midget car racers.
The Offenhauser engine, familiarly known as the “Offy”, was developed by Fred Offenhauser and his employer Harry Arminius Miller, after maintaining and repairing a 1913 Peugeot Grand Prix car of the type which had won the Indianapolis 500. Impressed by the double overhead cam, four-valve-per-cylinder design, which was a great leap forward at the time, they designed an engine on similar principles.
From 1934, through the 1970s, the Offenhauser engine won the Indianapolis 500 27 times. By then, the company had already been sold, right after World War II, to Meyer-Drake, who continued to build the engines. From 1950 through 1960, Offenhauser-powered cars won the Indy 500 and achieved all three podium positions, winning the pole position in 10 of the 11 years.