Hello, I have always wanted to know the answer to that question. Everyone says that the internals to so very diffrent then stock, yet no one really seems to know. There really isn't a whole lot that could really be diffrent. For starters it most likely has much better piston rings, diffrent pistons maybe, and should have stronger rods. Could the cylinders walls be over bored? probably not. The heads could be modified, but i would belive that they would be untouched. The idea in any company is to produce reliable results with as little changes as possible. Increase the piston, rings and rods give it the added strength. Who knows, the motor could stock. - Shain #10140