Fully leaned out, my two MVVS 49s can hit 14200 and 13800 rpm respectively (the higher rpm from my older silver-head) using the APC 12.25x3.75 on 5% fuel (both equipped with mini-tuned pipes). Using this prop, I tune it on the ground for 13500 or so. That being said, I personally like the APC 11.5x4 prop better on my fun fly models as throttle response is better IMHO.