I googled your model number and found a belt listing--no year I.D. though..its made by Rally/Roper,and the belt# for the blades is (Sears) 58577,and the drive belt is 58406..I looked at the "Vintage Sears Tractor" web pages,they mostly cover suburban's and customs..I think the year is incorperated into the serial number,I'm not sure which digit it is though..