Early And Late Hemi Engines
Early Chrysler Hemi engines were produced from 1951 to 1958.
It was the design of the Hemi head that really stamped the Chrysler, Dodge and De Soto engines as being different yet unique.
The Hemi headed engines were already common in Europe, mainly Grand Prix race engines, with the valves open and shut by twin overhead camshafts.
Chrysler decided to adopt a different approach, instead of leaving it's single five bearing camshaft in the vee of the bent eight, they chose to run adjustable pushrods up in a straight line to work short and long rocker arms, pivoted on parallel rocker shafts.
The hemi design was the choice for such marques as Duesenburg, Stutz, Miller and Offenhauser.
During World War II, Chrysler was engaged in the development of aircraft engines and a V-12 tank engine which were to use the Hemi head.
The first late Hemi engines were offered in 1964, it took a couple of years before consumer demand forced Chrysler to build street versions of the Elephant.
These engines were regarded as polluters and the last of the great Hemis became extinct after 1971. Now you can purchase new Hemi blocks and cylinder heads.