To each their own on brand / weight, conventional or synthetic , depends on each specific application and build needs. This has been a heated topic for many , and some will argue till their death on what brand, or what weight to use to try to convince you what to use, i think world wars could be actually started on this subject. I'm a firm believer on what the manufacture guild lines recommend. With that being said, our beloved cars are now 31 to 41+ years old, and many improvements to oils have been made in the past few decades. One really needs to research the market for what best fits your own personal needs and engine builds, because their may be an oil out there that's better and can out perform what your currently using . Also ZINC has been removed from most oils in order to prolong the life of our Catalyst converters, a primary lubricant additive now only found in "High Mileage" oils, or in over the counter specific additives. Me personally, I like to use Synthetic 10w30 Mobile One high mileage, and change intervals of 3,000 Miles, that's JUST ME. Please share your ritual and what Oil you use and why. would love to see the responses/conversations here, let the wars begin lol