Introduced in 1953 as the M170 military version, the civilian CJ-6 made its debut in 1955 as a 1956 model. It was stretched version of the CJ-5 with a longer-wheelbase (101 in, 1955-1971 / 103.5 in, 1972–1981). The extended chassis allowed a variety of configurations, including adding a second row of seats. The M170 military version shared many of the features of the M38A1 (Military CJ-5), but had the passenger-door opening extended back to the rear wheel well. As in the CJ-5, the V6 and V8 engine choices appeared in 1965 and 1972.