i use mobil clean 5000 oil and a AC Delco pf47 on everything i have in my driveway
i let it go to atleast 4k before i change it on the 05 blazer and my mom’s 03 impala
i wait for the oil life to get down to about 25% on my dad’s 05 malibu
and on my 01 S10, i use 3.5q and 1q of lucas stabilizer because it stopped the rear main from leaking! if that motor ever dies, the truck gets the LSx swapped in finally