The tire size looks like 8:25x20 or possibly 9:00x20. 8:25x20 was the standard size for the model as I recall. If the rear is vacuum it is a 15K rated GM unit. The hinge for the equipment body appears to be located behind the rear wheels as that is exactly the bed longsills and frame meet. Could you be mistaken about this? Are you certain that those are not the winch cylinders you spoke of? I've been around this stuff for 40 years and have yet to see lift cylinders mounted at the hinge area as there is no leverage at that point. Photos are too dark to see what is up front where I'd expect to see them.
I think I see an Oliver decal on the door. Man that would be so cool to restore and then haul an old Oliver tractor around.
