Stainless Steel Exhaust Manifold with Integrated Catalytic Converter (452025) by MagnaFlow®. Position: Rear. Primary Tubing Diameter: 1.5". Collector Outlet Diameter: 2.5". Color: Silver. Header Coating: Uncoated. If your car needs replacement, install one that will get you through the smog check. This converter is part of the exhaust header/manifold assembly, and it will directly replace the factory unit, with little or no fabrication required. The Direct Fit Catalytic Converter with Header is available in Pre-OBD II and OBD II configurations.