Thermostat housing

[ancientcityRRT]

I have a leak in my thermostat housing on a 2000 XLT with the OHV engine. All I can find is the 35mm housing as opposed to the 40mm housing. Can I use it or does it have to be the 40?

 

[swshawaii]

Four Seasons 85668 or Dorman 9021012.
http://www.rockauto.com/en/catalog/...ystem,thermostat+housing+/+water+outlet,10337