For clarity, *many* modern oils do not have the same zinc levels as old oils, but plenty of them still do. A reasonably high quality oil that has a good supply of zinc is Mobil 1 High Mileage in 10w-40, which is a good match for the 2.8. I personally use Motul 8100 5w-40 (full syn) or 6100 10w-40 (semi-sym) or Lubromoly 10w-40, as these are all approved by Ze Germans for long interval changes and work great in my other cars, which are largely turbocharged. These oils are all $35-$45 for a 5l jug on Amazon or AutohausAZ - not free, but affordable especially when you do 5k or 6k change intervals. If you go down this route, just be sure to use a high-quality filter that can put up with long changes - I use the oversize Wix 51036XP (ACDelco PF52) for a little extra filtering, and a little extra capacity (plus it's the same filter on my Suburban and Fleetwoods
). Don't use cheap store brand or orange filters for extended changes.
[This message has been edited by thesameguy (edited 09-12-2014).]