After reading endless pros and cons on this issue it comes down to one, and only one question to me. How long are you going to live with the engine? If you are giong to tear your engine down as I do every 10K or 20k then mineral oils win. If you are going the distance, say 100,000K or better, then the synthetics win.
Unless you are racing of course. Then the synthetics win every time, for lots of reasons. Another thing, if you are running a roller lifter motor, (sans-385?)
oil is the guy that cools your complete valve train. And again, synthetics direct heat away from the valve train a bit better.
I've had bearing problems/issues on the bottom end with Royal Purple oils and soft bearings, but I had good results with Mobil-one 15/50 using those same bearings.
Down through the years, I've never had a engine failure that I know of, that I can relate to a mineral
oil failure. And believe me I've really screwed some engines up bigtime too!
I guess the short answer to this question is to be realistic about your intended useage. Good luck!
cobrashock