what oil to use

Not the way I read this.
http://www.amsoil.com/articlespr/article_xl7500.aspx

http://www.upmpg.com/changes_xl-7500.htm

But that's today.
Tommorrow may be different.:-k
Thanks, I didn't know that. XL is their cheapest stuff. I didn't look at it. I only looked at the stuff that they market for performance applications. I stand corrected. I should not have said "everything they make now" when I did not look at their cheap stuff.