Best way I have found to get the right belt length is to take an old belt that is to long. Cut it in two. and feed it around where an original is supposed to be. Mark the spot where the end of the belt meets the other end. Then measure the belt from the cut end to the mark. If a belt tensioner is used on this set up you will have to have the tensioner in contact with the belt during the measurement, just not fully extended. Good luck. Rog