Eric, I have a Ford 515 with 6 ft bar on my B7100. The only difference between the 501 and 515 is that the 501 uses a pittman arm and the 515 has a wobble box on the bar.
Muleman, the only things I had to do when I attached it to my Kubota was to deal with the breakaway bar and a lift arm that attached to an offset drawbar on the Ford. The breakaway bar is made to attach to the stabilizer connection under the axle of the Ford tractor. The Kubota's don't have that point, so I just did away with the breakaway bar and put a chain with a weak link up to the tractor end of my 3 pt hitch arm. I think anything I might hit that would pull on the link would probably pull the front of my B around. Here are some pictures of mine before i added the chain and the drawbar connection.
I have an owners manual for the 515. I you will PM me, I can send you a copy.
John