I rebuilt the entire box with a new core, two years ago. After looking at heater cores from a number of sources, my recommendation is go with someone like Rockauto or Advance because they all appear to come from the same place (China). I paid under $50 for mine. Only thing I had to do was resolder the plate that holds the two pipes together to get a better fit into the housing. I have never had a problem and you can pressure test before you install to be sure.
Where I didn't scrimp was on the rebuild kit -bought the DMT kit, and it has everything including new housing clips, flap material, seals, etc. It will save you time and grief. The pleasure of hearing the internal flaps work cleanly is worth the price in itself.
Being a non-AC car, to take the heater box out is not a bad job. Just take pics every step along the way as you disassemble. It's easy to cross a wire or forget where and how a plenum cable is oriented and attached. If your car was like mine, at the same time you do the core, also replace the cardboard in the glove box. You can watch and get the box plus new screws for $20. Much easier to do with the heater box out of the way.
Where I didn't scrimp was on the rebuild kit -bought the DMT kit, and it has everything including new housing clips, flap material, seals, etc. It will save you time and grief. The pleasure of hearing the internal flaps work cleanly is worth the price in itself.
Being a non-AC car, to take the heater box out is not a bad job. Just take pics every step along the way as you disassemble. It's easy to cross a wire or forget where and how a plenum cable is oriented and attached. If your car was like mine, at the same time you do the core, also replace the cardboard in the glove box. You can watch and get the box plus new screws for $20. Much easier to do with the heater box out of the way.