Ken, good answer but I need to make minor correction. Your comment "These belts are used for a 318 Quick hitch, PTO drive kit, and 47QH snowblower." The belt drives the quick hitch pto drive kit which drives the input shafts for the model 47 and the model 51 broom.
TMAC, Deere also manufactured a 540 rpm drive which you could connect to your elevator or any other small farm equipment that needed 540 rpm input shaft. M120551/882 where the belt used to drive this appartus. There is other belts using this secondary pulley to drive hydraulic pump for Deere 44 loader and other loaders that offered a pump to run the loader functions. The second pulley is what allowed you to leave your mower deck installed and use other front mounted attachments. Sometimes.