I cleaned some more of the paint off of the serial number tag and it is stamped M610 and 213621. Bobcat didnt recognize the 213621, they said it isnt long enough to be a serial number but then again they couldnt really answer any of my questions except after referring to the manual they said it looked like all M610's had tapered shaft engines. They did however give me the number of a guy who only works on the older belt drive models and has so most of his life, he's retired but by the sound of it has a huge shop at his place with Tons of spare parts, he still works on them in his free time and he's not to far from me. According to him all M610's were tapered shaft and with mine being a straight shaft he's thinking someone had the sheave machined to accept the straight shaft. Plans are to take the machine to him so he can go over it and see what we can make work. That may be awhile though, we got a foot of snow the other day and the next two days is suppose to be bringing more.