Barry, Roger Howard had some heater parts for sale, although I don’t know if he has a core – and, if he does, if he’s selling it separate from the other parts:
The heating system consists of the following:
1)a heater “core” (small radiator),
2)a plenum to cover it,
3)an interior fan and housing, and related vacuum actuators and tubing,
4) the hot water control valve
5) the pushbutton controls with cables.
I have several “used” interior fan and housing units with cable controls, I have some pushbutton controls (buy maybe no plastic pushbuttons?) I have some hot water valves.
This is not enough to make a heater. You would do better to contact a s…
Dan