I believe the reason the Mobil 1 15w50 has escaped the ax as far as ZDDP is concerned... while all of the other standard 'off the shelf' Mobil 1 viscosities got cut to around 800... is that it is not a 'standard' viscosity recommended by any current auto manufactures, and is labeled as 'Racing' on the bottle. It's a great, very affordable oil for flat tappet cams, dirt bikes and various air cooled engines.CamKing wrote: ↑Sat Feb 29, 2020 12:42 pmThere's a few really good "Off the Shelf" oils out there. I don't recommend them, because the large companies have a history of changing an oil's formula, without ever telling anyone. There's a much smaller risk of that happening with a "Not for on-road use" oil.n2omike wrote: ↑Sat Feb 29, 2020 12:27 pmI've always used Mobil 1 15w50 synthetic in all my flat tappet and air cooled (yard/motorcycle) engines. Have used it for decades. It's the only Mobil 1 grade that has a good ZDDP content at 1300 ppm. Can usually pick it up at Advance Auto. 5 quarts with a Mobil 1 filter is often on sale for around $35. Can sometimes find 5 quart jugs at Walmart for around $28.
One thing I will give you on your statement... is that you are correct that oil formulations can change without warning. It's best to keep an eye on their websites, or to make sure the bottles recommendations do not change.