Loading...
Starting at $434.95, AutoBuffy stocks 9 catalytic converter with exhaust manifold assemblies from MagnaFlow, Walker, and Eastern Catalytic. This combined unit bolts directly to the engine's exhaust ports, converts harmful combustion gases into less toxic emissions, and routes exhaust downstream. When it fails, you face failed emissions tests, power loss, and potential engine damage from back-pressure or heat.
Because this assembly combines two critical components, the biggest decisions are OBD-II compliance (CARB vs. EPA), construction quality (direct-fit vs. universal), and substrate type. A direct-fit unit is almost always the right call — it retains all factory O2 sensor bungs, brackets, and flange positions so no fabrication is needed. Make sure any unit you buy is certified for your state's emissions standard before ordering.
| Option | Best for | What you get |
|---|---|---|
| Direct-Fit OEM Replacement (EPA-compliant) | Most drivers in non-CARB states who want a bolt-on repair with no cutting or welding | Exact flange match, pre-installed O2 sensor ports, stainless steel construction, meets federal EPA standards |
| Direct-Fit CARB-Compliant Unit | Drivers in California and other CARB-adopted states where stricter emissions laws apply | All direct-fit benefits plus an executive order (EO) number for legal sale and use in CARB states — required to pass state smog inspection |
| OEM / Dealer-Sourced Assembly | Owners of newer or warranty-sensitive vehicles who need guaranteed fitment and OE-grade metallurgy | Highest material quality, exact factory spec, longest expected lifespan, but typically the highest upfront cost |
| Performance High-Flow Assembly | Enthusiasts seeking improved exhaust scavenging and modest power gains while remaining street-legal | Less restrictive substrate, mandrel-bent tubing, still meets EPA standards — note: not legal for sale in CARB states unless EO-certified |
This job is rated Advanced primarily because exhaust manifold studs on higher-mileage engines are frequently seized, requiring penetrating oil, heat, or stud extractors to remove without snapping them into the head. Once hardware is free, the assembly unbolts from the cylinder head and the downpipe, and the new unit installs with fresh gaskets and new fasteners. Reinstall O2 sensors, clear any stored codes, and run the engine to confirm no leaks before returning the vehicle to service.