If he looked in the bores, and you looked in the bores, where do you think the rust came from?? Is your garage heated? Or heated only when you are working out there?? Was this motor a deal, so to speak, or do you feel you paid top cash for it, meaning how much are we talking here? You must have had some inkling that no matter who built it, if it was sitting around for a while ( you haven't really said how long, or where and how it was stored ) , and then it took you a while to get it going, there could be a possibility of problems, right? Just saying. Motors are not always prepped for storage if the builder doesn't know your intent, and you stated you are three owners down the line (or more)....