64 valiant heater box rebuild

If not a factory AC car, you could do it a few hours if no issues. But, there are always issues. You will likely need to treat rust, paint, fix cracks and such. At a minimum, clean out all the leaves and wash to remove mildew. I recently refreshed the non-AC box in my 1964 Valiant. I used a copper heater core. I recall the box said Made In Canada. I use Evans Waterless Coolant, so no concerns with it corroding. I also put a stainless screen under the cowl vents to stop tree junk from getting in.