This relates to another thread just posted. There are many different opinions on the subject. RL says wait 3k before switching. Yet, many cars come factory fill with M1. I don't think it really matters but I would break it in on dino first. What type of car?
It will not negatively effect break in at all.If you have not nocked down the major asperitys in 1000 miles then something is wrong.Hondas come with a long life breakin lube. Guess what oil Hondas break in lube most looks like? It is the closet we have seen a dino oil come to Redline like additive levels. Research has demonstrated that high levels of moly and zink will help rings properly wear in. If my memory is right moly was preffered by coated rings and zink was preffered by plain iron rings.
I think it was an SAE paper co-authored by Lubrizol and Toyota.