The Offenhauser or "Offy" is a racing engine that dates back to the 1950s. It features a revolutionary design that casts the block and cylinder head as one piece, eliminating headgasket failures under high compression and boost. This Indy car is a 1972 Chassis that won the 1973 Indianapolis 500 with Gordon Johncock at the wheel. it's 4 cylinder, 159 cu.in Offy engine makes over 700 horsepower! | Hemmings