Sorry for late response.... Holidays. Synthetic will be more stable under most conditions. It also doesn't break down viscosity as soon as Conventional lubricants. Full synthetics, like Power Purple, Valvoline and Mobil 1 are all great choices and will last longer between oil changes than Conventional Oils because the viscosity stays more stable for much longer. However, there are some really good Conventional petroleum based oils that work really well, like Kendall.... it's not cheap and it's a bit hard to find, but I know racers that use it exclusively... and they aren't sponsored by them,,, they do very little advertising. I think most oils, Syn or Conv will work fine for most engines, from lawnmowers, motorcycles, generators and cars and trucks... and when changed along with new filters at proper intervals, most probably wouldn't be able to measure any difference in wear. Unlike Top Fuel Drag racing, where they dump the oil after every pass, there are much more extreme uses like offroad racing and such, like a long NASCAR race running very high rpm's that operate in much more extreme conditions.... that, I think you would see measurable differences in wear by using a Full Synthetic lubricant.