For racing applications you generally want less diameter and more pitch, as an example I have a DagoRed with a .91 4 stroke and run a 12x10 prop on 30% fuel and turn 11.5k on the ground.
Your rpm numbers seem low and with a pipe and correct prop I would expect to see at least another 2 or 3k rpm. You might ask some of you questions over on the Extreme speed plane forum here on RCU to get some prop recommendations, something likean 11x9 or 10x10 might be better. You should really flight test the props because the overall drag on the airframe comes into play also.