Fleet oil 15 w 40 having the API CI-4 Certification on the label.
Can be found in brands of Shell Rotella -T (Carefully read the API Spec)
Chevron RPM Dello (Carefully read the API Spec)
Exxon Fleet
Napa Fleet
If you are way rich nothing will keep it from going to milk. If you can tune it to at least 20 % rich and no more the oil will again look like oil. The closer you get on your tune the better the oil will look.
Get a good easily servicable filter like the Pure Power, keep the tune up right and you will be amazed at how many passes you can make on the same oil.
Ed