If the center of the feedhorn throat isn't at the exact position as the previous feedhorn, the reflector will need to be aimed higher or lower to compensate for the offset. This will result in reduced performance as the reflector is not designed to converge the reflected signals at the adjusted feedhorn position.
You will probably have better performance if the original feedhorn/scalar is used then mount a voltage polarity switched LNB like the Inverto Black Pro. The OEM feedhorn/ Scalar is designed to illuminate the shape and FD of the reflector, but the aftermarket LNBF will over/under illuminate the reflector with generic round pattern.
You will probably have better performance if the original feedhorn/scalar is used then mount a voltage polarity switched LNB like the Inverto Black Pro. The OEM feedhorn/ Scalar is designed to illuminate the shape and FD of the reflector, but the aftermarket LNBF will over/under illuminate the reflector with generic round pattern.