Heck, thats just what ya need. Pete at wackerengines can fix you up with all the parts to put it on a plane for cheap. I'm just about ready to fly my Hanger 9 Super Cub with the 31cc ryobi and his 2" mount and muffler was just the ticket to get that long motor under the Cubs cowl and keep from cutting it up. And yes, I mounted the motor WITHOUT the need to push back the firewall too Piper