As far as the cast iron age strenghting, I guess I will have to eat crow on this one. When I was in school I recall studies showing that this did not occure or that the statistical data did not prove that it did. At the end of this article I see that some cast irons do not age and others do depending on the nitrogen content.

http://www.moderncasting.com/archive...402/99-191.pdf

FWIW doubt it's going to make a huge differance on how we break in our engines.