1988 GMC K1500 Engine: 4.3L V6; Standard Rotation; Optional Heavy Duty Thermal Fan Clutch; OE Fan Clutch Height; Fan Mounting Holes are 5/16 In.;. 1988 GMC K1500 Engine: 5.0L V8; Standard Rotation; Optional Heavy Duty Thermal Fan Clutch; OE Fan Clutch Height; Fan Mounting Holes are 5/16 In.;.
