I yall dont like the oil we have today just wait. The newest spec for all the majors is GF-5 and it will be rolling out very soon. the trend is lower viscosity and less anti wear. All new engines made today are roller everything and to be honest with you they dont care about the guy with the 40 year old technology flat tappet or hydraulic flat tappet cam. Bite the bullet now and go to a hydraulic roller or your problems will never go away.
If you take into account rebuilds and expensive oil additives a hydraulic roller is not that expensive. I have yet to have seen a lost cam lobe that didnt put metal all through the system and not eat up parts.
The guys that are in trouble are the guys with class restrictions that have spec cams.
All oils are changing and unless you find some that has been sitting for 10 years your in trouble. If you do find some it has an expired shelf life and the good stuff has most likely fallen out of the blend.