Block rated for 800, pistons for 6. Clutch is something cheap and will ultimately be the defining factor. Its supposedly rated for 400trq, which is well over what I expect. The plan is to keep it on pump gas and I don't like the idea of anything over 500whp on that. When it comes to making power there shouldnt be any guesses. You build for what you want to make. The plan was always 500 and the bits I got that made it capable of more were unexpected gifts