Despite what many people think or believe, Chrysler did not invent the Hemi engine. The French had a hemi-head engine in a Peugeot in the early 20th century. During World War II, Pratt and Whitney radial aircraft engines used hemi heads.
Alan R. Welch and his brothers, owners of the Welch Motor Car Company, are credited for pioneering the hemispherical engine. The power plant was a simple 20-horsepower, 2-cylinder engine with a single overhead camshaft. Although the General Motors discontinued the HEMI in 1910 when it bought Welch, Peugeot developed its own hemispherical engine. BMW mass-produced a HEMI version before Chrysler engineered it for modern use.
