Also.... Have the oil tested for the driving you do. Just because someone can go 10k
on the oil doesnt mean that you can. Contaminates and the HPOP in every 7.3 kill oil. It is very
rare to find any truck that can go over 5-6k before the oil needs changing using test results.
Just because the bottle says you can run it twice as long, it may not be true in your
engine. If running a bypass filter, intervals can usually be extended much longer.
Use a name brand oil, get it tested, change as often as the tests say so.
I change at 5k because that is where the Delo in my engine starts to break down and
the contaminates start heading up.