http://www.mbca.org/tech-talk/tech-articles MBCA Documents\Engine Oil Technical Presentation, Every gearhead has an opinion about engine oils; each has a favorite oil that he or she knows with absolute certainty is “the best oil in the world.” "1947 – 1975 gasoline-engine vehicles, use CI-4/SL, Mineral base if less than 3,000 annual miles; use CI-4/SL Synthetic base if over 3,000 annual miles. Warm-up for ~15 seconds and drive lightly until at operating temperature. and Do NOT put an after-market ZDDP additive into your crankcase on any engines.
Use ONLY the correct oil for your engine as produced by the oil company. ZDDP additives can create ash and sludge when added to an existing oil formulation. You don’t need that problem."
Find the whole slide set if you like data over opinion. Sorry, you won't find much more than opinion and bias on gas. I do know: In California "the" gas formula is strictly regulated and passes serially from the very few refiners through the same supply lines to the different gas companies' depots. IMO, they are formulated the same without enough differences to make any difference. And Oil performance is regulated and tested
My experience since 1970: My 250sl has used the
cheapest regular gas I can find: usually ARCO. I also use the cheapest oil but correctly spec'd 10-40, changed at 3k driven or not. More than once, it has sat for at least a year with no starts. It always starts right up! I have never used additives. But I do understand and use timing advance. I now live at 2000 feet so I can run most year at 10 degrees advance w/no ping. If it pings just reduce the advance to make it happey. I have 86K on the motor and just took the head off: I just started commuting 100 miles a day and wanted to change the chain and make sure the gasket, valves, and cylinders can take the abuse. Wow, very clean. The valves look new and no deposits to mention, no valve issues except for 2 rockers that have some wear at the valve pads, cam is great. The gasket was a little shaky between the cylinders.
I am currently adjusting the FIP using premium and when I'm done, I'll go back to regular and see if it has any effect.