Copes 71 Dart Swinger Rattle can resto. (Lots of picks not for dial up)

Replace that housing. I had to do the same thing on my wagon, mine looked similar when I went to replace the thermostat. New thermostat and and housing were less than $15 at Kragen. Not much more than a rattle can.

My waterpump had both of the hose fittings almost corroded off also. that was $45 + gasket goo. I had never done any of this stuff before, but these cars are so simple and cheap to work on.

Good luck.