I now have 984,000+ miles on the factory reman of my Detroit 60 pre-emission. All original. It has gotten CK rated oil from the time that Schaeffer first offered it. Wear numbers are virtually unchanged from when the engine had only 40K miles on the reman and still uses oil at the same rate as it has its entire time with me... about 1 qt per 11,000 miles. Last oil change, at 978,415 miles, 21156 hrs, with 22,693 miles / 491 hrs on the oil, the Iron was 16, Lead 6, Chrome 1, Copper 1, Tin 0, Aluminum 3.
The oil change intervals are 50% longer than the OEM recommended drain interval of 15,000 miles / 300 hours.
Oh.... and it has gotten 10w30 in winter and 15w40 in summer. CJ-4 initially then CK-4 when it showed up. Schaeffer syn blend. Both of which are on the Ford approved list if that matters to anyone. Even during all the controversy about CK-4 and Ford, the Schaeffer CK-4 made the approved list with Ford.
Probably should add... the add pack showed Boron 26, Moly 72, Calcium 2010, Phosphorous 1238, and Zinc 1016 on the UOA.