52K not a drop, Either Mobil 1 or regular Valvoline, depending on my mood or what I have in stock. If I go Mobil 1, it'* 10W-30 as that'* what I keep stocked up on for the GTO to help quiet down it'* valvetrain and keep it from triggering the knock sensors with false knock. I also add Lucas Synthetic stabilizer. If I go Valvoline, just regular oil Lucas stabilizer.
I change mine in all my vehicles every 2,500 miles (even the GTO and Bonne with M1). I don't give a rip what anyone says, what manufacturer'* say is "ok", or the boastful claims of oil manufacturer'*. I spent way to many years working in service seeing engines that were grenaded because the owner neglected to change their oil based on those above mentioned claims. I firmly believe in the "Spend a little now, or a lot later" theory, and since I keep most of my vehicles well past 100k, I'll spend the money.
In spring/summer, I typically go with a 10W for the added protection against thermal breakdown in the higher temps, in fall/winter, I typically go with a 5W (except the GTO), to aide in quicker pumping when it'* cooler, as oil thickens up as it gets colder out.