It seems there has been several threads discussing what weight of oil to use and how it affects cam timing and what I'm curious about is how certain oil additives may effect cam timing as well. Why I ask is because I have seen Carrol Shelby promoting Z-max (on the speed channel) as a product he stands behind and that it is added to every car they build. If there was one person in the aftermarket automotive industry that I trust and respect, it would be Carrol Shelby but I'm just wondering if anyone has first hand experience with this product and what they think of it.