<P> The sixth generation F - series was introduced in 1973 . This version of the F - series continued to be built on the 1965 fourth generation's revised platform, but with significant modernizations and refinements . Front disc brakes, increased cabin dimensions, gas tank relocated outside the cab and under the bed, significantly improved heating and air conditioning, full double wall bed construction, increased use of galvanized steel, SuperCab was introduced in the sixth generation pickup . </P> <P> The FE engine series was discontinued in 1976 after a nearly 20 - year run, replaced by the more modern 351 series (Modified) and 400 series engines . </P> <P> In 1975, the F - 150 was introduced in between the F - 100 and the F - 250 in order to avoid certain emission control restrictions . For 1978, square headlights replaced the previous models' round ones on higher trim package models, such as Lariat and Ranger, and in 1979 became standard equipment . Also for 1978, the Ford Bronco was redesigned into a variant of the F - series pickup . 1979 was the last year that the 460 big block engine was available in a half ton truck . </P> <P> The 1980 F - Series was redesigned with an all - new chassis and larger body; this was the first ground - up redesign since 1965 . The exterior styling of the truck was redone to improve aerodynamics and fuel economy . Medium - duty F - Series (F600 - F900) were also redesigned; although they shared the cabin of the smaller pickup trucks, the largest version of F - Series now wore a bonnet with separate front wings (like the L - Series). Medium duty Ford F - Series would carry the 1980--1986 interior design until 2000 (though pickups were restyled again in 1987 and 1992), with very subtle changes such as window glass and electronics . </P>

When did ford come out with the f150