I just always hear about people saying you have to break in a rebuilt more for 2k miles, 1k miles, 5k miles, whatever.... just wandering what is the reason behind it/how it will break in better than just driving the crap out of it? asking because I was talking to an experienced builder in CO(won't say his name), who was saying he's built pleny of motors for track cars(which just go straight to the track), and that they last just as long as ones that don't get broken in. also, because I just put the new motor in my car, and have no way to break it since its not street legal. I've had 1 track day with it so far, and it ran great, no problems. total of ~ 160 miles on the engine now, and its runing great, and its had absolutely no break in. same with my roommate's car. except his only has ~ 30 miles on it.
I will do compression tests on both to see how they are doing... btw, these are both TII motors.
but just kinda wandering about this.

anyway, post up any thoughts. thanks!