Which oil manufacturers recommended that? I have a good friend who is a Jaguar Master Tech, he and all the techs there swear by, "If you ever put anything other than 100% Synthetic oil in an engine, it's useless to ever put in synthetic oil. Use a synthetic blend if you've ever put a non synthetic oil in a engine."
Roller cams may have a big thing to do with whether or not you use a conventional/synthetic oil for break in. I'm not sure though, it's just a guess.
Red Line
