I believe they did. The recirc heater with the round coil used the two hose holes spaced vertically quite a distance apart, and attached with 3 studs extending thru the firewall. See the attached pics. The fresh air heater may have used the holes toward the outboard side of the firewall with the fan motor sticking thru the firewall where the cover plate is in the pics. I'm not sure if there were also attaching studs going thru the firewall, but suspect there were. My firewall is peppered with holes in that area. (Not sure at the moment what they're all for.) There's also a pair of holes closely spaced vertically toward the center of the firewall, which may have been used for a different style heater (there were more than 2 types used.) Someone else will have to weigh in with a picture of the other heater styles.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
