Tony,
I have been watching this thread & just seeing how it all pans out....
I see what blown is saying. We are human. The fact is, the guy who traded you believed it was a 400. Maybe the guy before him thought it was a 400 too. Who knows, it is best to work it out before you decide to pull out both guns & start blazing. I mean, you didn't get assaulted by a criminal & left for dead. You got the wrong motor, it's not the end of the world. You can get a attorney & you can roll the dice. Is that really going to fix this? Are you prepared to WAIT a long time to possibly get awarded a victory from a defendant who still has no money??? Then what? Garnish his wages in small increments? Don't hold your breath.
I am not an expert on 400's... but what Blown said I also have heard. It is no secret the 400 is thin on the cylinder walls & is prone to overheating. I am glad to hear that you did not get a "305"... face it, it could have been worse & I am sure he is not the first guy to mistake a 400 for a 350. So he made a mistake; a easy one to make assuming he could have been misrepresented too. So you want to HANG the guy for it????
Be men & work it out reasonably. Anyone can say "I'LL SUE!!" Everyone is so quick to sue everyone these days. I agree that you should have gotten what you were told, but I have a feeling that if you calm down it can be worked out. You have made it very clear that you will sue him, trash his reputation, etc... get on with it or work it out. I really don't believe he meant to rip you off. Scooter