1979 GMC P3500 Engine: 4.8L L6;Automatic Transmission; w/o A.C.; Position: Fan, Alternator and Air Pump;. 1979 GMC P3500 Submodel: Step Van - Van; Engine: 7.4L V8; Position: Power Steering;. 1986 GMC P3500 Engine: 5.7L V8; School Bus; Position: Fan and Alternator;.
