I think that's old wive's stuff. Kind of like the idea that switching to synthetic on an older car will cause seals to leak. It's not really the oil that causes the seals to leak, it's the old and warn dino soaked gaskets that can't take a cleaner, more homoginized oil. I don't know if there is any truth to the "break in with dino juice" philosophy, but I highly doubt it. Just do your first couple of changes earlier than you normally would to expunge any metal shavings left in the engine during the manufacturing process.
Okay, I guess my father in law is an old wife. Here is his tale. He builds Toyota indy motors. So, save for Gadget, he knows more than YOU. On HIS motors, the 2 this year in the 500, they do the break-in with regular motor oil, and do the break-in in a RELIGIOUS manner. Then, they switch to synthetics. Synthetics can provide TOO much lubrication, not letting rings seat into the walls properly. Plus, on a plain bearing engine, the crank journals need to seat themselves, too. So, take it from him, wait for the first 2 oil changes to do the switch. Now, when I used to race motorcycles, a long time ago, the same rule applied for the vfr hondas I rode. So, if you know more than Mike Velasco, let me know. I wanna hear it. :xdevil: