The powertrain line of this generation underwent multiple revisions through its production. At its launch, the engine line was largely carried over from 1979. While the 7.5L V8 was dropped entirely, a 4.2L V8 was introduced as the smallest V8 engine. For 1982, a 3.8L V6 became the standard engine for the F-100. For 1983, to improve the fuel efficiency of the model line, the M-Series engines (the 5.8L "351M" and 6.6L "400" V8s) were dropped; the latter was replaced by the return of the 7.5L V8. In response to low demand and poor performance, the 4.2L V8 and 3.8L V6 were phased out in 1982 and 1983, respectively. For the F-250 and F-350, a 6.9L diesel V8 (sourced from a partnership with International Harvester) became an option for 1983. For 1984, a "H.O." version of the 5.8-L V8 was introduced. The 5.0L V8 was fitted with fuel injection as standard equipment for 1986, becoming the first such engine in an American-market pickup truck. The 4.9 was fuel injected on 1987 models.