What I am trying now is making a1/4" thick firewall to epoxy in the existing one so I can install a .65 K&B sportster and see how that works out to keep the 3.5" CG. I have that brass heavy hub that I put on the .65 shaft because the mockup I did was showing me that even with a .65 it's still going to be tail heavy. The issue I have now is the brass hub is not moving. Don't know why. It is the same shaft as the .45 and it comes on and off the .45 without any issues. By not moving I mean I got it on but it is not coming off. I tried to unscrew it and the shaft ended up unscrewing from the engine instead. I wrapped a towel around the exposed shaft to protect the threads and put a clamp on it as tight as I could without ruining the threads and it still didn't come off. So my only choice is to work with it only it didn't screw all the way down so I put the stock washer and nut on it too.

Please tell me that the shaft thread is on opposite direction of the prop rotation. I don't want to try this if there is any chance of the shaft unscrewing from the engine whether that be on the ground or on the air.