The Chrysler 300 "letter series" are high-performance personal luxury cars that were built by Chrysler in the U.S. from 1955 to 1965 and were a sub-model from the Chrysler New Yorker. After the initial year, which was named C-300 for its standard 300 hp (220 kW) 331 cu in (5.4 L) FirePower V8, the 1956 cars were designated 300B. Successive model years were given the next letter of the alphabet as a suffix, reaching the 300L by 1965, after which the model sequence was discontinued while the "300" remained. At its introduction it was advertised as "America's Most Powerful Car".

The Chrysler Hemi engines, known by the trademark Hemi or HEMI, are a series of American V8 gasoline engines built by Chrysler with overhead valve hemispherical combustion chambers. Three different types of Hemi engines have been built by Chrysler for automobiles: the first from 1951 to 1958, the second from 1964 to 1971, and the third 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 designs. The engine block and cylinder heads were cast and manufactured at Indianapolis Foundry.