I also have a 149 and a newly acquired a1 tiller, the guy gave me the old junk belt so I could take to get a new one . Took it to Napa and the guy measured it to be 144 by half inch. So he ordered me the 144 part number belt. Next day on the way home with it I look at the box and it says 142" by half , low and behold it barely reached the center of the tiller pulley. Any way he said that was the only thing close that he could get. Tried another supposedly 144 from a small engine shop, same thing 142 inches. I just ordered a 146 from auto parts store. Will pick up in the morning and report back. My local cub dealer said that part is no longer made for ih or cub cadet . But I'm going to check another a little further away .

$84.12 from these guys.
http://www.cubcadetpartsnmore.com/m5...2-x-143-8.html

If you encounter a blockage while tilling the small one from the tiller to the mount will slip before the long one does, or at least in my experience.

Ok got that belt yesterday and it fit perfectly , tilled most of the day yesterday and about an hour this morning. It never jumped off or slipped once . I felt it several times during heavy tilling and was barely warm . Still looks like new . Very pleased for $38 . Its actually a 146 by half .

On way out to shed to get the brand and number.

Its a Gates Hi-Power II A 144 . But right under that it says "1/2x146 "