This is a widely discussed topic in many car forums. I don't recall any deep technical discussions in this forum. I can't remember what ratings have sufficient zinc and phosphorous but you need to look for 1200 ppm+ of each according to some of the experts. Some folks recommend adding wear or break-in additives to increase the levels of these components. The Zn and P are also referred to as ZDDP. Some of the boutique synthetic and dino oils have them as do some of the motorcycle oils. I run a roller cam so it is not an issue.