The Offenhauser Racing Engine, or Offy, is a racing engine design that dominated American open wheel racing for more than 50 years and is still popular among vintage sprint and midget car racers. History The Offenhauser engine, familiarly known as the "Offy", was an overhead cam monoblock 4-stroke internal combustion engine developed by Fred Offenhauser and Harry Arminius Miller. Originally, it was sold as a marine engine. In 1930 a four-cylinder Miller engine installed in a race car set a new international land speed record of . Miller developed this engine into a twin overhead cam, four-cylinder, four-valve-per-cylinder racing engine. Variations of this design were used in midgets and sprints into the 1960s, with a choice of carburetion or Hilborn fuel injection. When both Miller and the company to whom he had sold much of the equipment and rights went bankrupt in 1933, Offenhauser opened a shop a block away and bought rights to engines, special tooling and drawings at the bankruptcy auction, and he and other former Miller employees took over production. They and former Miller employee, draftsman Leo Goossen, further developed the Miller engines into the Offenhauser engines. In 1946, the name Offenhauser and engine designs were sold to Louis Meyer and Dale Drake. It was under Meyer and Drake that the engine dominated the Indianapolis 500 and midget racing in the United States. In 1965, Meyer was bought out by Drake, his wife Eve and their son John. From then until Drake's son John sold the shop to Stewart Van Dyne, the Drake family designed and refined the engine until its final race days. One of the keys to the Offenhauser engine's success and popularity was its power. A 251.92 cubic inch (4,128.29 cm³) DOHC naturally-aspirated four-cylinder racing Offy with a 15:1 compression ratio and a bore and stroke could produce at 6,600 rpm (1.77 hp per cubic inch, 81 kW/L) making it remarkably power-dense. Other variants of the engine produced even higher outputs of 3 hp per cubic inch (137 kW/L), unparalleled for their size and capacity in power-to cubic-inch/cylinder-count ratio. Another reason for the engine's success was its reliability. Its monobloc construction made it immune to head gasket or cylinder stud problems, and allowed for higher cylinder pressures. From 1934 through the 1970s, the Offenhauser engine dominated American open-wheel racing, winning the Indianapolis 500 27 times. From 1950 through 1960, Offenhauser-powered cars won the Indianapolis