Gear Vendors in but big engine problems

Document everything before you send that motor back. Have the shop that has it now take pictures and detail their findings. Once Superior gets their hands on the motor, all of the evidence becomes suspect. I would also refrain from stating how far you drove the car when the noise started. Not to be deceitful, but did you actually clock it ? It may not have been as far as you think and can't only hurt your case if you state otherwise.