I wouldn't say hes a scammer..... more of a novice or beginner engine builder! I would NEVER buy an engine from someone who does not have a good reputation on the forum in which hes listing parts.
As for his trade secrets, ummm I guess not knowing what you are doing is a secret?? Clearly he does not know, or does not care at all. The pictures of this block and findings are horrifying! Sorry to see people get screwed like this, good thing you didn't just drop it in. Most of the members here are not as knowledgeable as you were sir. Id be willing to bet 90% of them would have just dropped it in and it would have obviously failed. Then this seller would have blamed it on the buyer some how, because he thinks hes a pro with his "trade secrets" and all.