Call John at Old Air in Fort Worth TX. I recently installed the "Hurricane" in my 1946. It is the same size as a stock heater (like a 12" cube). The other manufacturers are 18" wide and there isn't any room due to the recess in the center of the firewall. You would have to space it way out from the firewall. Then you will loose ALL of the glove box instead of 2". If I had put my unit lower it probably would have cleared the glove box.
It was not difficult to install. Unfortunately I have not taken it to get it charged with R-134 yet so I cannot talk about how cool it is. I have heat, defroster and ambient air at this point. I hope to be inspected and get plates in the next month so I can follow up later with how cool it works. Be aware that you need to insulate the cab first.
1946 Chevy Half Ton ('56 235, '86 T5, '79 Camaro Z28 rear end, working on the '85 Jaguar XJ6 IFS)
1976 Margay Panther X, MC91B
