The fourth generation of the Ford F-Series is a line of pickup trucks and commercial trucks that were produced by Ford starting for the 1961 model year. Sleeker and wider than its predecessor, the 4th Gen F-Series was powered by a selection of inline six and V8 engines. The main variants were the F-100, F-250, and F-350, but Heavy Duty variants were also built. In addition to standard variants, a number of these trucks have been turned into Custom vehicles. Production of the fourth generation continued until 1966, when it was replaced by the Fifth Generation Ford F-Series.