Seriously, don't let the oil topic bury you. Some grades may be slightly better than others for a 4.2/4.0, but as long as you are in the ballpark there aren't any really bad choices. And living in CA, even in the high desert where you are, it isn't cold enough to worry about oil choices.
I didn't read your link above from BITOG, but anyone saying 10W oil is too thick to start a cold gas engine is just silly.
You can get Rotella 15W/40 in gallon jugs for a decent price over at the Pilot truck stop near you.