actually using the smaller carb with a macs quiet pipe set long would actually work well, the quiet pipe has enough back pressure to use the longer exhaust duration on the vr77... a 11x10 or 11x11 or a 12x9 would give some serious performance. no its not the normal pattern setup, but the smaller carb will throttle well with the above props as long as you use a pipe with more back pressure.

a examination of the helicopter engines used today will show that they generate huge torque with 10-11 MM.5 carbs and have good throttle response.