MACE 12MM MANIFOLD INSULATOR KIT TO SUIT HOLDEN CREWMAN VY VZ LS1 5.7L V8This Mace 12mm Manifold insulator kit suits Holden Commodores and similar platforms fitted with LS1 5. 7L engines. Manifold insulator helps to reduce the heat transfer from the engine to the intake manifold by spacing it up off the valley of the engine. Made from thermal composite material, this insulator will increase the engine power by keeping the intake cooler and increase low end torque by increasing runner length. Key Features: Reduces charge