Alrighty, checked the oil on the Durango, and after 3100 miles of stop and go, trailer towing, and the occasional fast ride on the HOV in 100 degree weather, the Hemi used @3/4 of a qt of MC blend 5w-20. Not too shabby! I'll run 'er out another thousand and change it out. Already have 10qts of MC blend in the garage ready to roll. I guess some Mobil 1 0w20 or 5w20 would be just what the doctor ordered for this kind of driving though. I am beginning to think 20 weight oils should all be synthetic.