I don't subscribe to the notion that you need an engine slathering rich for gallons on end to break it in.

A little extra rich for a few tanks is about it. 90 percent of ring seating is going to be done in the first tank anyways and I think its best to get them up to the temperature they are going to be run at to break them in properly.

Non ringed engines actually need to get hot to expand the top of the liner or you can end up damaging the rod and wrist pin due to the tight fit at the top.