Timothy T. If you have 8.50 rear tires, the tractor is under 36" wide. If your 147 has 10.50 tires, like mine does, it is over 36" wide and the rear tires will run in the "unplowed" snow and knock it down into the just cleared path. If so, you will be a lot happier with a "42". 36 and 42 are the width of the path it will make. Some people put wings on a 36, don't know how well that works.