MagnaFlow OEM Grade universal catalytic converter (51959) for 2020-2023 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD trucks with the 6.6L V8. Built to OEM Grade standards with a 3in inlet and 3in outlet, a 9in overall length and a 5in round spun stainless body, it uses a ceramic substrate and 16-gauge 409 stainless steel tubing for corrosion resistance and long service life. Federal/EPA compliant for OBDII vehicles with Federal emissions systems; not legal for sale or installation in California, Colorado or New York. Universal design with pipe (weld-on) connections requires cutting and welding to install.
Specifications
| Type | Universal catalytic converter (OEM Grade) |
| Compliance | Federal/EPA compliant (not CARB; not legal in CA, CO or NY) |
| Material | 16-gauge 409 stainless steel, ceramic substrate |
| Body | Round spun, 5in diameter |
| Inlet / Outlet | 3in / 3in, pipe (weld-on) connection |
| Overall Length | 9in |
| Sensor Ports | None (no O2 sensor bungs) |
| Part Number | 51959 |
This part fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2020-2023 | Chevrolet | Silverado 2500 HD | Custom |
| 2020-2023 | Chevrolet | Silverado 2500 HD | High Country |
| 2020-2023 | Chevrolet | Silverado 2500 HD | LT |
| 2020-2023 | Chevrolet | Silverado 2500 HD | LTZ |
| 2020-2023 | Chevrolet | Silverado 2500 HD | WT |
| 2020-2023 | Chevrolet | Silverado 3500 HD | High Country |
| 2020-2023 | Chevrolet | Silverado 3500 HD | LT |
| 2020-2023 | Chevrolet | Silverado 3500 HD | LTZ |
| 2020-2023 | Chevrolet | Silverado 3500 HD | WT |
| 2020-2023 | GMC | Sierra 2500 HD | AT4 |
| 2020-2021 | GMC | Sierra 2500 HD | Base |
| 2020-2023 | GMC | Sierra 2500 HD | Denali |
| 2022-2023 | GMC | Sierra 2500 HD | Pro |
| 2020-2023 | GMC | Sierra 2500 HD | SLE |
| 2020-2023 | GMC | Sierra 2500 HD | SLT |
| 2020-2023 | GMC | Sierra 3500 HD | AT4 |
| 2020-2021 | GMC | Sierra 3500 HD | Base |
| 2020-2023 | GMC | Sierra 3500 HD | Denali |
| 2022-2023 | GMC | Sierra 3500 HD | Pro |
| 2020-2023 | GMC | Sierra 3500 HD | SLE |
| 2020-2023 | GMC | Sierra 3500 HD | SLT |
Shipping
- Orders placed before 3 PM ET typically ship the same business day. Larger items ship within 1 to 3 business days.
- Standard, expedited, and overnight options at checkout.
- Oversized items ship by freight and take longer.
- Special order items follow a lead time we confirm with you individually before the order is committed.
- Backordered items ship as soon as stock lands. Lead times are manufacturer estimates and can change. Contact us for current ETAs.
- Need to cancel? Email us right away. Cancellations are not guaranteed once an order is in process. In-stock orders cancel free before they ship; a 6% fee applies only to confirmed backorders and special orders.
- International orders: prices do not include VAT, duties, or import fees. Your country charges these at import and they are the buyer’s responsibility.
Returns
- 30 days from delivery to request and ship back a return on new, uninstalled items in original packaging with all hardware.
- Standard returns: 8% restocking fee on the item price before tax and shipping. Shipping is not refunded in either direction. All waived if the item is defective or we made the error.
- Fitment guaranteed: select your vehicle above, or confirm fitment with us in writing before you order. If the part shows as a fit and it is wrong, the return is on us, even after installation. Otherwise, installed or used parts cannot be returned.
- Final sale: special orders, coilovers, electronics, engine internals, turbochargers, superchargers and turbo kits, unless defective or we sent the wrong item.
- Product images may be representative. The SKU and specifications in the listing are what ships.
- Email us for return authorization before shipping anything back.
Full details: Shipping Policy · Returns & Refunds · Warranty
