I have rebuilt several engines over the years,I helped with a late model race car as well.I have always used 10 - 30 when 1st starting the engine and run it at 2000 rpms for around 20 min.I never used a additive and use assembly lube when putting engine together.It has always worked for me,without problems.I don't use synthetic until after break in.It is to slick to let the engine break in.
