Some guy screwed me over, could I sue him?

So I had work done on my car. I told this guy I wanted my engine rebuilt. He suddenly texts me that it would be better and I would be happier if I go to a certain website (which he texted me the link) and get this motor, so him being the mechanic I trusted him. I got the engine he told me to get, had it shipped to him. So he gets the engine, puts it in and after its all in, all put together, already past the point of no return he texts me saying, it's the wrong sized engine, instead of a D15B7 it is a D15B6, I have lost 46 horse power in an already small engine. Ok so I ask him what should we do? He told me he contacted where the engine came from and they kept telling him its the same and they won't do anything about it. And i would have to pay him to put the old engine back in. So he ends up charging me full price for putting this "new" engine in although if he had just checked the engine before installing it he would have noticed it was wrong. I was pretty upset i paid that much for an engine that is smaller than what I wanted and he screwed me by putting it in before checking, but whatever I have an engine that I won't have problems with now. I have had it in my car for 4 months now and now it's leaking oil into the combustion chamber, the belts are squeeling. I'm very upset about this because now I have the engine I never wanted in there, and its giving me problems and I've only put less than 2,500 miles on it. What can I do about this? What should I do about this?