After much hesitation, I changed the oil today in my 99 7.3 using Supertech 15W40, which is CJ4/SN rated. After hearing nothing but good stories about it from some of yall on here who have used it in 7.3s, I decided to give it a shot. I've been using the Fram PH3786 filter the past few oil changes, it seems pretty well built. So far, so good.