Keyman, the motor was purchased on ebay. It was a new Anchor Lamina A62FM with foot mount. As others have said, it doesn't make a lot of difference what hydraulic motor you get because there are no real torque demands here; the smallest will work so I looked for a small one that didn't have a high max. rpm. I have seen videos where people have done this mod. and when rotated the chute would scream around. What they need is a hydraulic restricter in the line. Anyway, the one I bought has a max. rpm of 982 and it has turned out to be a good speed. If I had to go one way or the other from this I would choose a little slower.
After purchasing the motor I went about making a mount. I copied what "Dyer, retired" had done only used different materials. I used the same two existing bolt holes for the vertical piece where I used 1 sq. tubing and then made a horizontal piece template out of 1/4" plywood. When the template shape suited me I copied it to a 1/4" thick piece of steel plate. I then cut a piece of steel rod for a brace. I took it all to a local welder who welded it all up in less than 5 min.
I measured up the chute flange and entered the measurements into a CAD program which showed that 9 more teeth could be added with even spacing between all teeth. I printed this scale drawing and transferred the critical points to the chute flange. I then drilled out the base of the tooth valleys with a drill size with the correct radius (don't recall the size but close to 1/4" diam.). After drilling the holes I cut the sides of the teeth into the holes completing the tooth profile. I used an electric die grinder with a slitting disc but a hack saw would work fine here.
