The Chrysler Hemi engine, known by the trademark Hemi or HEMI, refers to a series of high-performance American overhead valve V8 engines built by Chrysler with hemispherical combustion chambers. Three generations have been produced: the FirePower series (with displacements from 241 cu in (3.9 L) to 392 cu in (6.4 L)) from 1951 to 1958; a famed 426 cu in (7.0 L) race and street engine from 1964-1971; and a family of advanced Hemis (displacing between 5.7 L (348 cu in) 6.4 L (391 cu in) from 2003 to 2024. Although Chrysler is most identified with the use of "Hemi" as a marketing term, many other auto manufacturers have incorporated similar cylinder head designs.