Just my non-technical 2 cents: 70 Ram Air III run 10-40 Syntec---10-40 cuz the manual calls for it and synthetic, just in case there is any true benefit-obviously I'm taking a chance that there is! The price BITES, but she's worth it!!
1983 Porsche 928S, ALL aluminum V8 w/ 1/4 million miles (never rebuilt)!!! No smoke, no burn! Can go 5K without adding oil. Change every 3-5K depending on time I have to spare. Have used 10-30 dino based, cheap local brand (MacMillan?? somethin like that) since 91K..can't vouch for what previous owner may have used. My mechanic..very well respected for talents/fairness with German/Italian (yea Ferrari/Lambo)/European street & race cars, has always said, "it really doesn't matter that much (for street applications!) what you use, just so long as it's always fresh and clean." Of course the newer cars that require synthetics, get it, no question! Knocking on wood!!...all I can say is we never find any nasty messages in the oil and as of 6 months ago she still holds original factory compression in all 8. And, yes, for most of those miles, I drove it like I stole it! I like to think this proves what he told me 160K ago, that I don't have to spend big bucks on oil, just keep it fresh! And since she holds 9 quarts I'm extra glad I'm not filling it with synthetics! German engineering? (maybe, but at 250K I doubt it), proof of the importance of proper maintanence (most likely!).
Now, with that in mind, even I would have to ask: why bother with synthetics in the goat? Simply because there is no question that the oiling and cooling and most every other system (except the freakin fuse box!) in the 928 is far more efficient and more advanced than the much older GTO. So, I give the GTO EVERY possible advantage that I can! Plus, most importantly, I love the ol' goat alot more than the old Porsche!!!
