1963 Dart L6 Heater Core

Just some random food for thought, it's been my experience that vendors often list parts for 64-66 and leave the 63 out as it's kind of an odd duck being a transition year and the vendors were uncertain. What works for the '64-'66 works for the '63. In fact I'm pretty sure I have a '65 core in my '63 right now.
As the years have passed it looks like vendors are catching up on this as I see the '63 being included more these days.

*Edit for clarification, this is my experience with the Valiant anyway, I do not know if the same situation exists for the Dart as well.