1978 GMC C25 Suburban 6.6L V8. 1977-1978 GMC C25 Suburban 5.0L V8. 1975-1978 GMC C25 Suburban 5.7L V8. Notes: Engine Water Pump Gasket -- Water Pump to Block; Paper. Ensure Proper FitTo confirm that this part fits your vehicle, enter your vehicle's Year, Make, Model, Trim and Engine in the Compatibility Table.