The oil manufactures are taking the ZDDP (zinc dialkyl dithiophosphate, basically meaning sulphur) anti wear additive levels way down because the sulphur degrades catalytic converter performance. The only way to ensure your flat tappet cam DOES NOT flatten lobes is to add ZDDP back into the oil. If your not running cats, add a full bottle of STP oil treatment, which is loaded with ZDDP, with your normal oil. Don't overfill it though! If you are running cats, just add like 1/4 of the bottle to the oil change. I have a 1981 Chevy C20 with a 350, flat tappet cam. I add just a quarter STP treatment every oil change and I still pass the emissions check. If you have any questions , let me know. Just using off the shelf motor oil your asking for it! Rock on!
