My takeaway was that Rotella is still a good oil for 4.0s as low revving motor and they do benefit from zinc. I think the article was just an expansion on the notion "one size (type) fits all" approach is NOT a good thing, i.e. that ANY diesel oil and/or high zinc oil is better for older engines, muscle cars etc. It basically reiterated that there are so many different oils because there are so many different applications, so do a little homework and find the right one for the best long term results.