Well thats what i always understood as being the case. I thought it would be very unlikely they would use a different pattern for casting x blocks. Not sure about sonic testing without boring, i have no knowledge in this area.
Did you look at how rough the bore was? Rough bored means just that. And it's usually pretty crude. This weekend I'll take a picture of a rough bored R block and post it up. It's basically impossible to get an accurate sonic test on a rough finish like that.
