The tech data sheet I'm linking below for Quaker State Defy 10W-40 is dated this year. It looks like it's out there, but might take some looking. Amazon is showing some in stock. It never was a big mover for us, so I'm not surprised if it's hard to find on the shelves. I do remember seeing it at WalMart and Advance Auto, but that was at least a couple of years ago.
Even though the QS Defy has the API rating of SN, only the 10W-40 grade has higher levels of ZDDP. Anything lighter than that, like 10W-30, 5W-30 or 5W-20 is "resource conserving" and as such is required to have lower amounts. Sorry, I don't have the access to the data as to exactly how much. https://www.quakerstate.com/en_us/p...b/001F9807_QuakerState_HighMileage_10W-40.pdf
You can see the relationship between the SN rated heavier oils and the higher levels of ZDDP in this data sheet for Mobil 1. It may not be up to the minute current, but it is recent. (Now I see it is dated October this year, so that's about as good as it gets.)
