I am out working on pulling the motor, the only reason I went with the Explorer block is it was newer and had less miles on it and probably wasn't driven as hard as a motor in a Mustang. I know the old motor was leaking some oil into the cooling system, thinking a bad head gasket. Once I have them both out and check them side by side I'll see about the bearings and go from there. I really don't know if I want to trust the new oil pump or not, I guess it will depend on how the bearings look. Not a Happy Camper today!