CAN'T FIND 1970 DART 340 HEATER CORE AND EVAPORATOR

Is yours a 1969. I think the only difference between 69 and 70-72 is the on inlet size is smaller at 1/2”.
to the OP, I think through researching the heater core for 70-72.5 is the same for AC and without AC.
No it's a 64, but it'd be pretty dumb to let something as simple as hose size hang you up, wouldn't it?