Thanks Steve for your reply, Yes the #5 mower was for the B, C, and CA it was different in some ways but they were all basically the same. I did find a parts list on the net and confirmed the mower.
As to the turnbuckles there would be two mounted on the back side of the tractor mounted from the hitch to the seat frame. My guess was they were to adjust or possibly hold up the hitch when the mower was mounted. They had a nut midway that you could adjust. Just wondering if they were needed and if so what for.
Now as to the pulley, I am not understanding matching the tractors rpm and pulley diameter. It would sound like I need to get a bunch made to figure out what one works. Don't have that time nor money was thinking it was just say a 10" pulley or something like that. The parts diagram only gave the description as pulley.