Ford 7710, Ford 550, Ford 1910, Ford 4430, KD Forklift, Ford LGT17H, New Holland L255 Skidsteer
I believe up to and including the 50D, the swing was a motor. The backhoe was a 54.
The 50H also had a swing motor. The 50H S had cylinders. Is it possible you have a 50H S or the backhoe from one? Do the cylinders look like this?