The LS9, of course, was the supercharged engine in the C6 Corvette ZR1. To support the higher combustion pressure and temperature that come with forced induction, the heads were produced with a unique Roto-cast method in super-strong A356T6 aluminum alloy. With the Roto-cast method, the mold rotates to more evenly distribute the molten alloy, creating a denser head casting that virtually eliminates porosity. And compared to the similar LS3 head, the LS9 features reinforced webbing and a thicker deck for greater rigidity and minimal distortion. The A356T6 alloy also manages the higher heat of a forced engine more effectively.
They can be installed on any LS engine with at least a 4.000" bore using standard 11mm head bolts.