stuck thermostat?

Not much of a test, but with the upper hose off and the belt off I can hear the impeller sloshing around as I move the water pump pulley


This is with the belt back on , sure seems to be flow in the coolant



For now I put it back without a thermostat
I should have time for a good shakedown tomorrow, see what it does


It certainly appears to be circulating.
Hopefully you just had a stuck thermostat like you suspected in the first place.