now you have the greatness of an ls1
I still want to know what heads you're getting... if built right with an ms4 you should be in the upper 400s to the wheels. You should hit 410-420 with the MS4 alone. If you don't already, get rid of the ls1 manifold and either get an ls6, or if you want to spend the money, get a FAST. With your big cam, I would rather get the FAST intake.