I have been using Mobil 1 5w-30 in my 4.7L Dakota for the last 40,000 miles (83,000 total) without a problem.
I have been running Redline 10W30 in my Challenger (360) for about 1000 miles without a problem. I broke it in with Castrol 10w30 (3000 miles) before using the synthetic. No problems yet.
Just remember that Rotella is 15w-40, that is the thick stuff like you said. If you go with synthetic, I would go with something a lot thicker than 10w-30, maybe 10w-40 or higher, because the bearings are use to something thicker.