10W40 is to thick for a new motor. 5 or 10W 30 is better for initial start up and getting that oil film in place.
You do not need any additives. You will add them because you were 'told it needed it' but no high performance production motor uses any additives off the show room. Again, see any production performance car since oh.. the 1950's
Breaking in with synthetic is also fine.
If I repost the proof from a GM lubrication engineer who says exactly what I am staying will you consider it or should I save the effort? Because, as mentioned... the engineers will do things for a reason.
Last edited by pfarber; 10/02/2014 7:29 AM.
