My dad bought a new model 18 from my grandpa in the late 1950s. It came with a Wisconsin engine but it was removed and the pto drive installed before we brought it home. It was a very good machine. My uncle had a model 15 which also had a pto. Back then you could buy a combine or baler equiped either way. New Holland still built engine driven balers for years. I think the Amish pulled them with horses.