Our readers keep the lights on and my morning glass full of iced black tea. As an Amazon Associate, I earn from qualifying purchases.7 Best Chrysler 300 Catalytic Converter | Stop P0420: Real Fix

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Walker, a Tenneco brand, manufactures a significant portion of the original exhaust systems found on Chrysler, Ford, and GM vehicles. The 54604 direct-fit converter carries that same OE engineering DNA — the flanges, hangers, and heat shields are positioned to match the factory undercarriage layout exactly, which eliminates the need for cutting, welding, or pipe bending. The 400-cell ceramic substrate receives an OE-style high-technology washcoat that mimics the factory’s oxygen storage capacity, so the downstream O2 sensor sees the expected switching behavior and keeps the check engine light off.

This unit covers the widest Chrysler 300 application range in the guide: 2005 through 2019 models, including the 3.5L V6, 3.6L Pentastar, and both 5.7L and 6.4L Hemi engines. The 2.5-inch outlet diameter matches the factory pipe sizing on every iteration of the 300, and the aluminized heat shields prevent radiant heat from degrading nearby wiring harnesses and plastic underbody panels. Owners who previously tried inexpensive universal cats report that the Walker unit cleared their P0420 permanently on the first attempt.

Several buyers note that the flange weld quality is consistent — the bolt holes line up with the manifold studs without requiring a pry bar or hammer persuasion. The one caveat is that a small percentage of units have arrived with the outlet pipe bend angle slightly off from the intended clock position, requiring a local muffler shop to tweak the alignment. For a premium direct-fit converter that behaves like a factory part, the Walker 54604 is the benchmark that cheaper knockoffs try to imitate.

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The 2016–2021 Chrysler 300 with the 3.6L Pentastar uses a specific left-and-right converter configuration that differs from earlier models. CIRconvert engineered this set with laser-cut stainless steel flanges that replicate the factory bolt pattern precisely — owners who installed these on Chargers and Challengers with the same engine report that both converters bolted up without the need to loosen the exhaust manifold. The set includes fresh gaskets and replacement bolts for the manifold studs, which is a critical inclusion since the original studs often snap during removal on high-mileage vehicles.

With a 50,000-mile limited warranty and EPA certification, this pair addresses the most common failure mode on the Pentastar — the passenger-side converter typically degrades first because it sits closer to the engine and receives more thermal stress. The 400-cell substrate is paired with a precious metal washcoat that keeps the rear O2 sensors within the manufacturer’s switching frequency window. Owners who paired this set with upstream oxygen sensor replacements saw immediate extinguishing of the check engine light without requiring a drive cycle reset.

The unit weighs 28.2 pounds for the pair, significantly heavier than budget single-cat offerings, because of the thicker stainless steel shell that resists thermal distortion over time. The only reported fitment issue involves the heat shield that may contact the transmission bellhousing on some 2018–2019 models, but a simple dimple with a hammer provides clearance. For 2016–2021 Pentastar owners who want a bolt-in solution that avoids the complexity of partial exhaust system replacement, this CIRconvert set is the direct match.

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PHILTOP designed this set specifically for the Chrysler 300, Dodge Charger, and Challenger with the 5.7L Hemi V8 spanning 2005 through 2022. The reference numbers cross-match over 25 OEM part numbers including Mopar units, which makes it easy for parts counter staff and DIY owners to verify compatibility. The kit ships with both gaskets and heavy-duty clamps so you can connect the converter outlets to the mid-pipe without sourcing additional hardware — a detail that saves a trip to the auto parts store during the install.

The stainless steel body is paired with a machined exterior finish that resists superficial rust better than painted surfaces. Hemi owners report that the internal substrate appears identical in cell density and washcoat color to the factory Mopar converter, which explains why the P0430 code on the passenger bank cleared immediately after installation. The 14.82-pound weight per unit indicates a solid substrate brick rather than a lightweight thin-walled can that would radiate excessive heat into the transmission tunnel.

One Hemi owner noted that the passenger-side flange weld was rotated approximately 12 degrees off the correct clock position on their unit, causing the converter shield to contact the floorpan. This appears to be a quality-control variance on individual batches rather than a design flaw, but it is worth inspecting the flange alignment before fully torquing the studs. For owners running headers or a performance exhaust, the PHILTOP set offers a good balance between cost and emissions compliance for a Hemi swap or restoration.

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For 2013–2015 Chrysler 300 owners with the 3.6L Pentastar, this CIRconvert set hits the sweet spot between cost and construction quality. The set weighs 25 pounds, indicating a robust substrate core and a thick outer shell that prevents the converter from deforming under the repeated thermal cycling of daily driving. The direct-fit design includes a complete set of replacement bolts for the exhaust manifold studs — a thoughtful inclusion because the factory studs on the Pentastar often corrode and snap flush with the manifold face, requiring extraction before the new converter can be mounted.

Owners consistently report that the bolt holes align with the manifold without modification, and the included gaskets seal the joint against exhaust leaks that would introduce false oxygen readings. The CIRconvert unit also passed smog inspection in Clark County, Nevada — a jurisdiction that follows California-style testing protocols — which validates that the substrate efficiency is sufficient to meet federal emissions standards. The 50,000-mile limited warranty provides some peace of mind for those keeping the car through multiple inspection cycles.

The only trade-off is that this set is designed exclusively for the 3.6L V6 — it will not fit the 5.7L or 6.4L Hemi models because the flange spacing and pipe routing diverge significantly. For a 2013–2015 300 with the Pentastar, this set delivers the same bolt-on convenience as the premium Walker unit at a more accessible entry point, making it the strongest mid-range value in the guide.

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A-Premium’s kit covers both the front and rear catalytic converter positions for the 3.6L engine found in the Chrysler 200, Town & Country, and Dodge Grand Caravan, which also means it crosses over to the Chrysler 300’s front converter location for 2011–2014 models. The kit ships as two separate direct-fit units with welded 2-bolt flanges on both the inlet and outlet sides, so you can replace the entire exhaust stream in one session without mixing parts from different suppliers. The included mounting hardware and heat shields replicate the factory’s thermal protection layout.

One Grand Caravan owner reported that after a set of cheaper converters failed to align with the exhaust pipe, this A-Premium kit fit without any clearance issues — the flange clocking and pipe diameter matched the factory mid-pipe connection precisely. The weld quality on the heat shield brackets held up during installation without cracking, which is a common failure point on ultra-budget units that use spot welds. The kit also carries a one-year unlimited-mileage guarantee, which covers both converters as a pair.

The disadvantage for Chrysler 300 owners is that this kit is designed primarily for the minivan and sedan platform with FWD configuration, so the pipe routing on the rear converter may differ slightly from the 300’s specific underbody layout. Buyers should confirm that their 300’s exhaust path matches the included components before committing. For owners of a 2011–2014 Chrysler 300 3.6L, this is a complete front-and-rear solution that leaves nothing for a muffler shop to custom-fab.

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PREMIER MILES targets the earlier Chrysler 300 generation — 2005–2010 with the 3.5L V6 — as well as the Dodge Charger, Challenger, and Magnum of the same era. The 400-cell ceramic substrate passes the EPA-mandated 25,000-mile long-term road test, and the company backs the structure with a 5-year warranty while covering emissions performance for 2.5 years or 25,000 miles. For a budget-friendly direct-fit converter, that warranty term is genuinely better than some mid-range competitors.

Buyers report that the unit is plug-and-play — the flange bolts directly to the manifold and the outlet connects to the factory exhaust pipe using the included hardware. One owner who previously dealt with a torn flex joint and a loss of backpressure stated that this converter was the only part they needed to pass state inspection. The polished exterior finish resists corrosion better than bare steel welds, which matters for cars exposed to road salt during winter months.

The main limitation is that this unit is only listed for the 3.5L engine — it will not fit the 3.6L Pentastar or any Hemi V8 because the inlet flange spacing and pipe diameter are specific to the earlier engine family. Additionally, the 15.47-pound weight is on the lighter side, suggesting a thinner gauge steel shell than the premium Walker or CIRconvert units. That trade-off is acceptable for budget-restored LX-platform cars that just need to pass emissions without a high-performance build.

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ZAIGANMA’s catalytic converter is the entry threshold for Chrysler 300 owners who need a single front replacement on a strict budget. It fits the 3.6L Pentastar engine across the Chrysler 200, Town & Country, Dodge Grand Caravan, Journey, and Avenger from 2011 to 2019 — and by extension, the front position on a 2011–2014 Chrysler 300 with the same powertrain. The unit contains platinum, rhodium, and palladium in the washcoat, which is the same triad of precious metals used in OEM converters, and it has passed EPA compliance testing.

Owners report that the welds are clean and the flange alignment is correct in most cases — the converter mounted without the studs binding or the flange rocking on the manifold face. One buyer in Clark County, Nevada passed a full smog inspection with this unit, confirming that the emissions reduction efficiency meets the federal threshold. The polished stainless steel body adds some corrosion resistance, and the included hardware eliminates a last-minute parts run.

The most significant compromise is the absence of a heat shield bracket. If your original converter had a factory heat shield, you will need to either transfer the shield from your old unit or run without one — the latter risks elevated transmission and floor temperature on long drives. A small percentage of buyers also reported that the flange did not align with the exhaust pipe on 2018 Dodge Grand Caravans, suggesting that late-production 3.6L engines may have slight variations in the pipe routing. For a budget-conscious replacement on a 2011–2014 Chrysler 300, this unit gets the job done if fitment is confirmed beforehand.