AC/Heater Box R&R in a 74 Dart

Yes, you will need to depressurize the A/C system and then disconnect the 2 aluminum tubing fittings for the evaporator on the firewall in the engine compartment. You will need to remove the A/C outlet vents assembly (2 screws on the bottom). You will need to remove the glovebox liner to access some evaporator bolts, wiring, and vacuum tubes. You will need to remove the passenger kickpanel and the lagging screw which bolts the right side lower dash to the body (will allow some flexibility when lowering the evaporator box.) According to the shop manual, which I advise obtaining, you will then remove the radio and ashtray assembly to access some more screws to then get the heater box out (I have not had to do this on my heater core as is ok, 1974 Dart Sport.)