I have no clue. I've done my best on this, this time. I'm not going to get ugly about it. All I'm interested in are facts. So far, I've seen none.
In the end, all these old motors really care about is if the dipstick says full. IMO, after camshaft break in with some kinds break in oil with some good zinc content, and good camshaft break in paste, you can really probably run anything off the shelf. I just prefer to have oil with a high ZDDP content. Been runnin it about 8 years in my truck. No problems whatsoever yet. Broken multiple camshafts in using it. Narry a problem there, either. I will continue to use what has worked.