I don't know if i mentioned it on here before or not, but i went to a seminar last Sept. put on by Joe Gibbs Driven oil & hosted by Lake Speed Jr. was very, very good. even before the seminar we were using J.G. BR/XP-4 (same thing). only thing we could get some flat tappet stuff to live on, during break in. helps not only cams but ring seal a bunch too. i'm not getting into great detail...don't have time, sorry. quickly...as for API ratings & whatnot, since Joe Gibbs oil is not on the retail market, (never will be acording to them), Wal-Mart etc. they don't have to adhere to government standards (for emisions, detergents etc.) so they can build the oil how they want too. as for Rottella T. yes it's diesel oil but what it has is more Zinc & Moly, that's the key to that stuff. the government ratings for diesel oil changed a few years ago & i think it's set to change again in 2010, getting worse each time. by the next change, 2010, there won't be really any benifits to using it any more
. could go on & on & on...gotta go. hope this helps some of you...a little.