So I am swapping my engine either this weekend or next weekend. How long do I need to break this engine in before I can start to rag on it? It is not a brand new motor although it does have low miles and is not being opened up at all. But who knows when the last time it was started.
^ Agreed.... if you don't know where that thing has been, which you usually dont, just be nice to it for the first couple hundred miles. Once you are sure that everything is running smooth.... than start really driving the thing.