Ok thanks yevgeni.. um, yev. I ask because even an emissions legal 454 with good heads, headers and dual cats should be able to make 400 crank hp. But the stock L29 manifold is really bad. The air comes around the runner in the top half, then is forced straight down past the injector, then has to turn a sharp 45 into the head. I see room for minor smoothing and blending, but no way to straighten the path enough to make it really flow. So if the 0411 can run speed density, then maybe it can run any direct port setup, like an Edelbrock 29045 manifold/injector setup.