Thanks for all your comments. Since posting, I have totally confirmed that the Mobil1 5W40 MSP is THE oil I will have to use. Received reply from Pennzoil and the closest thing they have is one used in Europe and not yet availble here.
I guess, as much as anything, I am VERY annoyed that I am so locked in when the world used to be open.
Sold my '85 with 365K when I bought the new one...and it seemed happy with simple regular oil changes with good oil!
martin