Yeah I'd say your low needle is too rich. From my experience on this engine you can leave the high needle at factory setting (1 7/8 to 2). Only lean the low end until, as Geist says, it starts to hesitate on transition. When it does this, I richen it back a little until it will transition again. One thing you will notice immediately when you lean your low end is that the idle RPM goes up significantly. That's because your engine is starting to fire almost every power stroke so naturally the idle RPM will raise. I always have to reduce the idle trim when I do this. Also the idle gets smoother and so does the midrange. This is an easy fix for you.