[A. Souphound]

It sounds as if you are experiencing the same problem as discussed in the tread on "overcooling". The problem identified was a stopped up heater core. Make sure the heater cable is connected, and feel the heater hoses, if they are not hot...no flow.
I've had an 'airlock' in the heater core after the anti-freeze was changed. To make sure this is not the case, with the engine running, loosen the top heater hose enough to let the air out. If that was the problem the hose temperature will start to rise.
Alvin