Try an oil that is for diesel engines. Rotella by Shell used to be the one to get, but I think they have reduced the zinc and cadmium levels in it. Valvoline racing oil still has the good stuff in it.
Another alternative is GM EOS now sold by AC Delco, P/N 10-106 is the new part number
Last edited by 302 Z28; 09-23-2008 at 11:03 AM.