Rick,
I not sure of the horsepower rating but from real world experience the 120NC has a ton of power. I flew a 120NC in a 1/4 scale Edge 540 that weight 11.5 pounds. I used an APC 16x8 and it would turn 9000+ RPM's. Hauled it around with great authority. I put the same engine in a 120 sized pattern ship spinning a 15x11 and I was getting 9300 static. A few great things about YS motors is the throttle response, low end tourqe, and built in fuel pump. I can pretty much say without a doubt the YS line of 120's will out turn Saito or OS.