Mobil1 0W40 used to be my go-to choice, problem is they changed the formation in May of 2022 and dropped the phosphorus to 900 and the zinc to 1000.
https://www.mobil.com/lubricants/-/...-1/pdf/emsga-mobil1productguide-v2-9-1-22.pdf
Those numbers aren't too bad, but I know most people would like to be up around the 1200 range.
This is why it's not OK to think "I've been using such-and-such brand for X number of years and never had a problem" when using an off the shelf oil. The manufacturers are constantly changing the formulations to meet the latest standards, so what worked for your last oil change may not work for your next oil change. If you're using a specialty oil like what
@Scody21 was just talking about then you're probably fine, because those oils are designed specifically for the application. Otherwise you'll really want to research the current levels of anti-wear additives every time you go to buy oil for your flat tappet engine.
