The subject of reduced zinc in oil sold at the counter is finally getting some notoriety with a national monthly magazine. For the older flat tappet engines it plays havoc by wearing the camshaft down quicker. Cam today...gone tomorrow. Check out the link........

http://blogs.mustangmonthly.com/6439...you/index.html

Several years ago another monthly magazine published an article on the same subject. They have an addition recommendation to use SM-type oil and adding one-half ounce of General Motors (or Government Motors as it is more commonly known today) EOS (Engine Oil Supplement) for each quart installed to improve it's anti-wear characteristics. Do not add more, more is not better. This has been my choice for the last year and half. So far, so good.