Use a bottle of GM EOS with every oil change. I will not start a race motor with out it. After every two races I cut the filter and check if for debris. I also compare my filters with other people that do not use a Zink additive. Mine are way better. A friend of mine who bracket races Kaw motorcycles was having cam issues. We finally talked him into changing to Rotella with EOS. A whole season with no issues. Even if your using Rotella, or an oil with Zink, the EOS additive is extra protection. Especially with a high performance motor. I could write two dozen stories about people I race with that are now believers. From an engineering stand point, I spent hours reading every article from every university research project I could get my hands on. The evidence is overwhelming. Earl We had a discussion here a while ago on break-in oil. The most recent Mopar Enthusiast magazine has an article on oil in general. The article says to always use oil with zinc for our old cars, not just to break in the engine. Some highlights in the article: It says that in the future Shell Rotella oil, and other diesel oils, will be no longer adding zinc. A new API "SM" standard will force that. Mopar Performance is rumored to be bringing out a zinc additive to make current oils compatible with older engines. Crane and other cam manufacturers sell an engine break in additive that you can add at each oil change and use regular oil. For now, look for API ratings of CF, CF-2, CF-4, CG-4, CH-4, CI-4, or CJ-4 on the oil bottle. CF-4 has a lower zinc content than other C ratings. Racing oil and some motorcycle oil (Harley Davidson Syn3) have zinc, as does Royal Purple synthetic with an SL rating. Gary H. ---- Please address private mail -- mail of interest to only one person -- directly to that person. I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic. Thanks! '62 to '65 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html. ---- Please address private mail -- mail of interest to only one person -- directly to that person. I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic. Thanks! '62 to '65 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html.