RE: Why is Engine Mount Set off Center
Yeah, compensating for the right thrust angle. There is a yaw effect seen single prop planes due to p-factor and asymmetrical flow. The right thrust is designed to help offset this yaw. It is not possible to ever get the right thrust “perfect” as the yaw effect varies with speed and throttle. So what is generally done is the right thrust is set for cruise speed. Basically every plane needs some right thrust for more honest tracking, the amount varies, but it is typically a couple of degrees.
Because of the right thrust angle the engine is set at, the motor mount will need to be attached to the firewall off center to compensate such that where the crank meets the prop is back at center. This would mean the mount is shifted to the left on the firewall (looking from behind as if you were in the cockpit.)