Smog pump.. also known as the AIR PUMP.

casting # 7817872 MAY.. be on yours as shown.

• Leave details please of the year and engine type on completion of the order, if needed.

• Make sure to test your Air Pump Check Valve for proper operation. A defective check valve will allow harmful exhaust gases to enter and destroy a new Air Pump.

• A NOTE ON SMOG PUMP CARE.... Preventing Smog Pump Seizures

  Smog Pump failure is usuall caused by Gasoline, exhaust fumes, oil, or water entering the unit contaminates the bearing grease causing bearing failure.

  Before installing replacement unit, test check valve(s) for proper operation. Air should pass through valve only in one direction. These valves prevent exhaust gases from entering the unit. DO NOT install pump with a defective check valve. Check the PCV system for proper operation.

  An inoperative or defective PCV system allows oil and gas fumes to enter Smog Pump, causing bearing failure.

  Water contamination causes bearing corrosion, internal component damage, or housing failure. To help prevent this problem, carefully inspect all hoses, make sure fittings are secure, pump filters are not clogged, and the fan is not damaged. Be careful when washing the engine and, on low-mounted units, avoid driving through high water.

• Cover pump when washing motor.
•  NOTE: Remanufactured AIR PUMPS are tight when first supplied and require an average
  500 mile run in period during which time noise can be expected from the new unit.
  DO NOT OIL or Greeze the unit.. so not wash or hose the pumps ever. 

Fits but check this image against yours first.