Cabin Heat

This is a typically seen installation for a heat muff.
From what I understand It doesn't work very well.

  This one has a larger hose and looks like it might work alot better but it sticks
out quite a bit and I think it would pose a problem rubbing the cowl panels.

These appear to be heater core units, where they mount or how they hook into the system I've no idea.  I've had some of these pictures so long I don't even remember where I got them lol.