It also makes me wonder about the wringing of hands on additives being removed from oil as well and flat tappet engines. There are still thousands of flat tappet engines out there including heavy duty/industrial Diesel engines still with flat tappet and not roller. Our engine oils are much better than they used to be regardless. I remember very well when lead was removed and one could say it was like the sky was falling with people thinking their valves would burn and needed lead for lubricant. How long did your spark plugs last? It was common to replace every 10,000 miles and I used to clean and regap them to limp them along another 10,000! At the end of those 10,000 they were finished and totally eroded. My 1950 Mercury had 40,000+ miles on the plugs and out of pity I purchased a new set. When I pulled the plugs they were still excellent clearly indicating the lead previously used was the culprit. It made me wonder how much it would shorten the life of the rings as well. Oh yes I even disassembled engines where the lead built up so severely on the valve stem below valve it tore out the guide as the valve opened and closed from the "cone of lead". The majority of the 80,000+ miles on my Mercury since total rebuild of the engine were after lead was removed and the valves and tappets are still fine. Ford had camshaft problems in the 50's and GM during the 70's and 80's and it was comical how badly worn they would become prematurely all the while using oil with zinc. It was common that if you overhauled or did a valve job on a small black Chevy you would change the camshaft. The oil is even more than good enough for the air filter as well especially when the cylindrical paper elements for the 50's and 60's are becoming difficult to get up here in the Snow Mexican republic of Canuckastan Use good quality oil, proper octane and of course proper maintenance and things will work just fine.