Greetings!  I have a Fox 40 stunt, p/n 40010, that I absolutely enjoyed flying.  Unfortunately, a few weeks ago I smacked the ground due to a loss of concentration  .  As a result the plane hit somewhat flat but the muffler struck the ground and snapped off breaking the front muffler mounting lug and the back end of the aft mounting screw hole on the aft of the crankcase.  In other words, there is only 1/2 of a hole on the aft of the crankcase and I was unable to recover the small part that broke off  .  It took me awhile to even touch the plane to begin repairs  but as of yesterday all repairs are completed and it is ready to fly again  .  I just bought a replacement Fox tilt down muffler on EBay.  I need some suggestions as to the best method to repair (if possible) the aft mounting hole in the crankcase or should I just dump the engine and find another?  I'd appreciate any suggestions??