Jay,

The 54 pickup that we are restoring had the recirculating heater in it. I have two restored fresh-air heaters but I think I will put the recirculating heater back into this truck (even though it will be a deluxe everything else cab).

That heater kept me warm in 8 degree temps on a 200 mile trip in Dec at night when I drove the truck from Teaneck NJ to my home in upstate NY. I was so warm (with no window seals) that I was driving in my tee-shirt.