It's been a long talked about subject. Patrick's recommends used Valvoline VR1 due to it's 20 ppm content. The American Engine Rebuilders Assosiation recommends Shell Rotella along with break in lube, and all of the cam manufactures pretty much recommend the same thing. All those people can't be wrong. If I'm not mistaken, the oil companies have been phasing zinc out since about 2000, my guess is that there has been alot of data since then to back it up. Especially in the form of flat cam lobes!
