H41 Strato-Ventilation was standard, whereas H51 and H53 were optional features. Going by the 1974 Operator's Manual, the handle for the four-speed blower is the same on H41 and H51, so maybe the blower itself also?
As there are no plugs going with Seb's H41 installation, international specs do make a difference here.
As there are no plugs going with Seb's H41 installation, international specs do make a difference here.