Kip Martin tells a story that a Ford engine was on a dyno, running. I think it was an automotive class and I can't remember if it was SBF or FE Ford. But he takes a breaker bar between the motor mount and applies pressure to the block. The engine slows down. A lot.
Just goes to show you cast iron isn't as tuff as you think!
* besides the normal align bore / hone to the mains, I would recommend the same to the cam tunnel. And always make sure came is straight.
I can hear the cash register now...