I am not quite sure why one would want to use an engine of this type unless the rules specifically require it. A ball bearing motor would be a much better starting place. In the case of rules requiring a bushing motor you could raise the exhaust port to help with running a pipe on it. Just know that messing with port timing is very critical and should only be attempted by those with the proper tools and skills necessary for this type of work. One small slip and a cylinder liner is ruined. You can also run a carb with a larger venturi size to get more mixture in and the transfer ports can be cleaned up to aid in the filling of the cylinder. Again, unless the rules require it I would choose a better piece to start work on.

This is in agreement with the above post. We posted at the same time.[8D]