Heater doesn't work so good - 74 Duster

Mopars either have too much heat or none it seems. Replace the heater core and be done with it. Flush never seems to get it back the way it should be. The new replacement heater cores are much more efficient and have about double the fins as the original.
Yes it does matter which way the hoses go on. I cant explain why but it does make a difference.