Throttle curve will not completely remove the step in rpm from a pipe that is too short. It might help a little depending how bad it is. Its probably going to lag until it hits a certain rpm and then take off. Throttle curve may just move that step in relation to throttle stick position.

Not that I pay much attention to it but, I heard you should not drill the prop with three holes all in alignment along the grain, may weaken the prop. Any thoughts?