When it comes to engine oil everyone has a preference or anecdotal evidence why one oil is better than another. On engines that have use engine oil pressure to adjust the valves (hydraulic lifters HLA) these engines need an engine oil that has low viscosity ( so oil is circulated around the engine quickly from a cold start up), and also an oil that has good detergency characteristics to keep the lifters clean internally. On engines that have mechanically adjusted valves and have higher mileage and perhaps have started to "burn oil" ,I would have no problems recommending a higher viscosity oil perhaps 10/30 thicker oil should give adequate protection and "burn" less oil. The key to long engine life is frequent oil changes!Synthetic oil is great but expensive, some engines require it yours doesn't.
A full synthetic oil. Either AMSOIL or mobil one. Both sell a full synthetic and semisynthetic, use a full synthetic. This is recommendation only if you want your engine to last a long time. Using a full synthetic is NOT expensive. It is cheaper than using a parafin based oil. You don't have to change the oil as often with synthetic. there is so many misconceptions concerning a full synthetic oil, down right lies.
I personally have changed over thousands of customers to synthetic oil. If ytou know what you are talking about the customer sees the value and improvement in the driveabilty in the vehicle.
I have been a AMSOIL distributor for over 30+ years. If you are interested in research it yourself, go www.amsoil.com and see for yourself. Some of the old diehards don't know what they are talking about. No offense Pat.