ls1 motors are not a GREAT boost platform. with 4 bolts per cylinder, the heads warp BETWEEN the studs with a lot of cylinder pressure. The heads themselves flow really well so that is its saving grace. You can still make big power (1000hp+ ) but you really need to make the whole setup as efficient as possible. Mine is one of those that is far from it. Intercoolers too small...turbos too small for the cubes....downpipes too small....but it is almost enuff power for my satisfaction.