Do you see a trim mistake by the factory? I made 3/16ths hard balsa side reinforcing plates that precisely locate the new firewall, they are held in place by Hobby Lobby's Superphatic. The firewall, 3/16 inch, is 30 minute epoxied on the sides, top and bottom. The engine mount is just barely long enough for the .10. You can see the 5 oz Harry Higley Ultra Hub holding the firewall in place. I used very precise measurements and cuts so the original down and right thrust would be be accurate.