I picked up my new to me 93 from the dealer today and it seemed to took a long time for the heater to get hot about 20 miles on highway driving 75-85. Is this normal outside temp was about 20 degree.

 

Its because you were at speed. when your crusing your radiator gets enough airflow to keep it chilled. If you let it idle while slowly driving in city traffic, then you will have plenty of heat.

 

Did you warm up the car before you took off? The heater core in the FD is not very big. Unless the car is at full operating temp, the heat is not very effective.
Also, the heat only comes from the floor vents and winshield defrost vents. If you have it at bi-level or dash vents then you are blowing cold outside air on top. For best heating capability, turn the vent control to floor only.