Fits: 1988–1993 Chevrolet C1500 1988–1993 Chevrolet C2500 1988–1993 Chevrolet K1500 1988–1993 Chevrolet K2500 1988–1993 GMC C1500 1988–1993 GMC C2500 1988–1993 GMC K1500 1988–1993 GMC K2500 Magnaflow13266MufflerThe MagnaFlow XL 4 X 9in. Oval Multi-Chamber Performance Exhaust Muffler 13266 features a straight-through, weight-optimized reversible design with a perforated stainless steel core featuring baffles and tuning gates, enabling it to deliver the powerful signature sound and dyno-proven performance that's made MagnaFlow a household name. Muffler 13266's oval-shaped, 4x9x18in. body and universal 2.5/2.5in. diameter inlet/outlet layout enables flexible installation options to match the spacing requirements of your vehicle. Professional installation is highly recommended. 13266 is produced using advanced CNC precision robotic manufacturing techniques and features durable, corrosion resistant stainless-steel construction, all backed by MagnaFlow's limited lifetime warranty.MagnaFlow XL 3 chamber mufflers use a unique combination of large-diameter perforated tubing and strategically placed sound baffles to reduce unwanted resonance and help your engine create horsepower. The sound baffles tune the sound waves using calibrated tuning gate openings that allow portions of the waves to pass through. These tuned waves reflect off the back wall of the muffler and cancel out unwanted harsher sounds. The large-diameter perforated core eliminates the flow restrictions of a louvered-style core. A careful balance between perforation size/spacing and the baffle tuning gate makes for great 3-chamber performance mufflers.