For what it's worth, my local NAPA dealer carries an extensive line of belts and has always been able to get me belts for things like mowers and attic fans, and they have cross-match information so they can look up the number on your belt. They have been much cheaper than specialty dealers in such belts. They also make a point of telling me that their belts that fit my mower deck are not guaranteed to last as long as "mower" belts, but in use they seem to hold up about as well.
Chuck