The stock heater hose routing goes from the intake manifold fitting on the front, passenger side of the manifold over the heater core and back to a fitting on the radiator. I don't think an '81 used the fitting on the water pump.
You have the right location for the temp sensor. Most folks will say that the head location reads a little higher than the intake manifold fitting, but mine seems to read about the same in both locations. If you have headers it might be easier to use the intake manifold fitting.