1997 GMC C6500 Topkick Engine: 6.6L L6; Standard Rotation; Severe Duty Thermal Fan Clutch; Marked GPK; w/ High Visiblity Hood;. 1998 GMC C6500 Topkick Engine: 6.6L L6; Standard Rotation; Severe Duty Thermal Fan Clutch; Marked GPK; w/ High Visiblity Hood;.
