This is a 28% WH Edge 540 with DA50 and stock muffler. To get the cowl on as cut in the picture, tilt the front of the cowl down and rotate CW about 45 degrees and then slide the cowl over the down tube of muffler. This should put the widest part of the plywood ring opening at the prop shaft. It takes a bit of turning and tilting, but you'll get the procedure figured out.