no "fresh air heater" in 57, that's what's referred to as the deluxe heater, as you'll see in the manual I linked in your other post .... not likely to find an off the self replacement, you'll need to find a rad shop that can re-core it
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
