Well, it's definitely not doing 167mph on that setup. RCSpeedo isn't always the most accurate tool.
2200Kv * 12.6V = 27720 RPMs
27720 * 3" pitch = 83160
83160/1056 = 78.75mph max-efficiency pitchspeed.
So if the plane had zero drag, the motor was at 100% efficiency, the prop put no load on the motor, and the battery voltage remained at its full 12.6V, then you'd still be able to go no higher than 78.75mph.
When we factor in losses due to drag and such, you're probably in the 50mph range or less.
At 167mph, the plane would be covering around 250 feet per second. To get an Assassin going that fast, you'd need astronomical amounts of power.