Pulsar PSR Turbine Housing T4 Twin Scroll 0.91 A/R 80/73mm TW for 300 Series Turbo 177208 Bolt-on 300 series turbo directly, no modifications required to fit. All housings come with an installation kit that includes: a stainless steel gasket for the inlet a clamp to connect the bearing housing Part 602330001 (Reference: 177208): 0.91 A/R, T4 Inlet Twin Flow, 4.21 Marmon Flange Outlet, 80/73mm Turbine Wheel Design Part 602330004 (Reference: 177211): 0.88 A/R, T4 Inlet Open, 4.21 Marmon Flange Outlet, 80/73mm Turbine Wheel Design Part 602330003 (Reference: 177210): 0.88 A/R, T4 Inlet Open, 4.21 Marmon Flange Outlet, 76/68mm Turbine Wheel Design