I agree it is a topic of debate but I will very respectfully disagree with you Showkey, especially when breaking in a flat tappet cam. You can wipe a lobe at break in using the wrong oil. Too high a viscosity, not enough zinc, any number of things related to lubrication, other then mistake or error. Or you can use an oil that is too slippery and prevents the rings from seating. But why take the chance. GM used and still uses their own version of break in oil for the same reasons that we do, to protect the motor at break in. So if anyone is asking my opinion, after you have spent considerable dollars rebuilding a motor, you should not skip using oil specifically developed for breaking in a new motor just to save a few (very few) dollars. Give yourself the very best chance of having no issues with a new motor. Just my thoughts on the matter.
