Upper Thermostat Housing for Mercruiser Ford based raw water cooled engines. Fits models 188 888 215 233 and 255. Held on with three bolts and had 4 hose ports which accept 1 inch ID hoses.
Replaces:62898A1

Lower Thermostat Housing used on Mercruiser Ford Based Small Block engines with Raw Water Cooling.
Fit fits Models 188 888 225 233 235 and 255 Ford Based Engines.
Has Four hose ports two to the back of each manifolds, one to the circulating water pump and the one to the raw water supply (either Raw Water Pump or Outdrive.
Replaces: 63588A1