Those are good prices, but within reason.. Not sure about the quality of his work. But what exactly are you asking? It doesn't look like a scam, but then again, how can you tell?

If you're looking for a 1st or 2nd gen, give him a call, and talk to him. Ask him questions, and figure out if it's a scam.. If he's ligit he should answer your questions honestly.. If it's a scam, he probably will be focusing on getting your money.. If you're looking for a 3rd gen motor, ask if he can build one for you. Or find someone else who specializes in 3rd gen motors