68 Dart Heater Core Replacement

The AC and non-AC ones are different. rockauto lists several. I don't know that one brand is better, and perhaps all come from the same factory. I think I have bought Spectra or such (Canada?). While in there, insure your drain tube is clear and that the galvanized drain pan hasn't corroded. That happened in my 69 Dart (factory AC). I soldered a copper pan underneath and around the drain tube to fix.