Replaced heating core and now no heat

I recently replaced the heater core in my 72 Dart Swinger, and now I have no heat. It also only blows through the defrost whether I select heat, defrost or a/c. I have also lost the ability to select heat or cool from the temperature slider. I have to manually twist the pivot point behind the glove box. I had a broken vacuum line tee that went to the carb which I have replaced. I am lost for answers.

Any input would help.

Thanks in advance - Jason