Steve,

I've never had the housing itself get bent in a crash, usually everything else will get busted before that could happen. Have you stripped all the head components off and left just the main shaft and gear on? Look closely at that when you add just a bit of throttle (enough to get it spinning), is there any wobble? Also check to see if the gear is firmly against the bottom bearing and the retaining collar is flush with the tapered end pointing down towards the upper bearing, also make sure the grub screw is tightened. Also, are you able to physically move the shaft side to side or up and down at all? You shouldn't, it should be locked in place nice and snug by the retaining collar. Hope this gets your problem solved.

Mark