UH Oh.

I don't understand why you don't find a good standard bore block or core and have your machine shop bore and hone it? At least this way you know the quality of the machine work, assuming you use a good machine shop.
It's hard to trust what your getting from junk yard blocks or private seller blocks, the person could be trying to recoup money they lost on a bad purchase and stick me with the loss, I got lucky once already and the guy is giving me back my money. just safer to do it with a guarantee backing it know what I mean?