The torque or moment of force is simply the product of the force value by the arm length with which the force makes the object pivot around its center of gravity. That torque is the intensity of the "pivotal action".
The arm length is supposed to be measured on a line passing by the CG and perpendicular to the line holding the force and its application point. If the engine is reasonably abeam the center of gravity, you can approximate this arm length with the distance between the CG and the engine.
So the effect of the torque will be higher if the distance CG-engine increases or if the thrust of the engine is higher. You will then also need a higher torque to counteract the engine torque and control the yaw motion of your aircraft, either by increasing the size of the tail fin or by putting that fin further aft.