In 1982, General Motors introduced the Chevrolet S-10 Blazer, and its rebadged GMC S-15 Jimmy variant, as 1983 models. They were based on, and co-developed, with the 1982 Chevrolet S-10 pickup truck, introduced one year prior, to replace the Isuzu-based Chevrolet LUV truck. Similar to the pickup models, these versions are sometimes internally referred to as the S/T series to denote two- and four-wheel-drive models respectively (similar to the full-size Chevrolet C/K trucks) despite all versions being badged with "S" nomenclature. Unlike their full-size K5 counterparts, the S-series Blazer and Jimmy did not feature removable hardtops. For their first eight model years, they were only offered in a two-door bodystyle; only in March 1990 were four-door versions of the S-10 Blazer and Jimmy introduced as 1991 models, with a 6.5 in (17 cm) greater wheelbase and length. While significantly smaller in all dimensions than the K5 Blazer, interior space was comparable or larger thanks to better packaging – the luggage area, for instance, was 21.0 cu ft (595 L) rather than the 20.1 cu ft (569 L) of the older, larger model.