Sorry, Tom, I think i misunderstood your first reply. I thought you were commenting against O'Reilly et al. in favor of OEM. I wouldn't know the diff... I been fortunate on the other vehicles to not buy many parts [including my three motorcycles ]. So I was looking for OEM delco or motorcraft and noticed that the sites reference the OEM part numbers, but what they are selling is an 'equivalent', ... i.e. O'Reilly, et al. part.
Going back to the beginning, there seem to be legitimate disagreements amongst good Ford owners as to whether Motorcraft NEW parts are always/only the best parts to use for such major surgery. I'm asking the question. I don't claim to know what is the answer.