question about factory air

[clemdaddy]

i want to replace the blower motor in a 66 factory air truck. the folks at 'old air products' in texas say that they don't show a listing on the blower motor for factory air but that they are different from the non-air heater motor. something about a bigger mounting flange.

does anybody out there know if later model blower motors will work, if the mounting flange is different? like say 73-82 model trucks.

thanks, clem