what oil to use

It seems that no matter what auto/motorcycle/truck website you visit the oil topic comes up. The biggest thing of all is, no matter what oil you use, change it often with a good quality filter (both oil AND air). Everything enters the engine through the carburetors so good air filtration is very important. If you own a car that has a cast iron flat tappet camshaft (which most of us do) and not a roller cam (which are generally made from billet steel) then due to the porosity and softness of cast iron it is important to use an oil with at least a .13% zinc content to prevent the lifters from scuffing the cam surfaces. On metal to metal surfaces like a cam and tappet rubbing together the zinc molecules help to create a smooth rolling surface,filling porous areas of the cam lobes. Should the oil breakdown or become starved the zinc becomes the only line of wear defense. Other things like lifters not spinning can also cause a cam lobe to wear. From what I`ve found the Valvoline VR-1 has the highest zinc content of .20%, Kendall GT-1 is at .16% ,Mystic JT8, Shell Truck Guard, and Spectro Golden 4, are at .15%. Shell Rotella w/XLA is at .13%. Many companies are very covert when it comes to divulging their numbers ,but if the product has a heavy metal or other potentially hazardous ingredient in it that could harm people or the enviroment, then legally the public has to be informed (somewhere) what`s in that product. Groups like the EPA and/or FTC could probably provide the 411 on the unknown oil numbers. That`s my last whack at the dead horse.