I used to run Mobile 1 when I had the cobra. After I did the Eaton swap I ran Penzoil Platinum up until the day I sold it. I also now run it in all 3 of my vehicles including my 90 Notch.
penzoil ultra 5w-30 if i can find it. if not, then castrol gtx or mobil1 EM. theyre all SN oils so its not like theyre high zinc. the detergents are the difference.