Color me stoopid too.
I'm running dino oil (Valvoline 5w-30w) in my chevy just to prove my theory that it doesn't make that big a difference what type of oil you use. 135k and it uses about 1/3 of a quart after 4000 miles.
It's got a couple of very minor oil leaks that I need to take to care of which should reduce the oil consumption even further.
