Forget about picking up 20 horsepower by changing motor
oil, even if you do, it would take a racetrack and timing equipment to notice the difference. Pretty much everybody I have ever spoke with is in agreement that
synthetic is far superior to mineral
oil as an engine lubricant. If you can afford it, use it. It will find a way to leak out of an otherwise leak free motor however. I am not a PhD in lubricative technologies, but I would still do the first 1000 miles on non-detergent mineral
oil, just like the old days. Maybe it's just superstition. But your motor would probubly prefer you take it relatively easy for the first few miles anyway, so having slightly inferior oil (mineral oil) in for those miles won't hurt you. Never tried breaking in a motor with
synthetic, so I can't say if it works as well or not. But to me, the risk of poor ring seal vs. the difference in engine wear because I used mineral oil for 1000 miles is a no brainer, I need my rings to seal, and these motors run a long time on mineral oil (maybe longer on
synthetic), but the loss of engine life because I used mineral oil for 1000 miles should be nonexistant.