What I've done on my '66 150F to allow me to better heat the interior is buy a couple yards of dense felt material and made a curtain that I velcro in place just behind the seats, closes off the entire rear baggage area which blocks any drafts that usually comes from the tail section and also makes for a smaller area to heat. I can take some pic's and post later, but this really works well for me!
I bet that would make a difference. I've got a roll of stuff that would be perfect. But should do a burn test before considering it for aircraft use. I'll burn a swatch and see what it does.
