I agree with Locomotion on the AMSOIL.

Click on the the provided link above, it's a Technical Service Bulletin from AMSOIL about Zinc and Phosphorous content and and Flat Tappet Camshafts.

Also, AMSOIL is the Official Motor Oil of the 2007 & 2008 AMSOIL/MOPAR MUSCLE ENGINE CHALLENGE as seen in Mopar Muscle Magazine. In the this engine challenge, engine entries are filled to capacity with AMSOIL #AMO 10W-40 Motor Oil. A lot of the entries utilize flat tappet camshafts to keep costs down. All the engines have to be able to reach a maximum RPM of 7000 RPMs, and do it six times during the challenge. After the challenge, the engines are torn down to make sure that the contestants used approved parts in their builds. Other notes are made such as how the engine bearings look. In all, they look brand new. In my opinion, the is a great testimony to not only awesome engine building, but also how well AMSOIL Motor Oil stands up in extreme conditions in high horsepower engines.