Big block 440 in 71’ Dart “Heater box does not fit”

Looking for some feedback from my Mopar brothers and sisters. I have a 71 Dart with a 440 in it. The previous owner deleted the heater box (and threw it away a month before I bought the car). He told me that the heads they put on the car when the motor was built did not provide enough clearance for the fan motor. He only drove it on hand picked days so he threw it all away (Fraaak). The car is an original A/C car but I would be satisfied with a non A/C unit for heating and windshield clearing on cool days. I was able to locate a damaged heater box from a friend to use for sizing. My question to you. Is there a shorter heater fan motor available that would fit the heater box. If so I will have to start looking for a heater box (A/C or non A/C hahaha). Thanks in advance Ron D