Pricey parts and hard to say, are the cylinders bored and what size are they? I believe those block came from direct connection with a 3.91” bore. Anything you buy new and have issues with you have recourse with the manufacturer. Buying used from a private party involves risk. Any big money engine parts I would buy I would have my engine builder check out first. I would have the block pressure tested, sonic tested and visually inspected.