Got the Ford 917L flail all put back together, I had a neighbor weld the shaft back into place. Next time I think I might haul it to somebody who is a welder. It took about 4 hours with an angle grinder to get rid of the excess metal.
I found it to be a bit tricky to hook up to, the offset seemed to cause me to miss the mark and back towards the center of the machine. After I finally got it all hooked up, it worked quite well. I cut about an acre of thick grass that had been previously brush hogged and it did quite well. I mowed at the maximum cutting height for the machine, about 5 inches. I then adjusted it down and cut another acre of thinner grass, going slow through the thicker portions and speeding up where the grass was a little more sparse. It did have a tendency to collect the previous cuttings on the offset side and dump them all at once, usually on a turn.
I did find out the flail mowers and steel cable left half buried by the previous owner aren't very good companions. I managed to quickly wind about 20 feet of it up in the mower before the mower said enough and stopped. Headed back towards the house dragging the remaining 80 feet of half inch cable behind me, After a quick run to the local hardware store to buy some cutting wheels for the above mentioned angle grinder and thirty minutes of cutting and pulling, I was up and running again. Only three knives were slightly damaged but otherwise things seemed pretty good. The cheaper make do knives from flail master worked very well. Only other problem I had was the clearance between idler pulley and the cover. It rubbed the cover enough to polish two little groves into the inside and burn two small spots in the paint on the outside.
I think that if I can keep ahead of the grass next year it will do a very nice job.