Gibson GP131S Performance Stainless Shorty Header for 2001-2003 GM HD 8.1L

Vehicle Fitment

• 2001-2003 Chevrolet Silverado 2500HD/3500 (8.1L V8; automatic trans)
• 2001-2003 GMC Sierra 2500HD/3500 (8.1L V8; automatic trans)
• 2001-2003 Chevrolet Suburban 2500 / Yukon XL 2500 (8.1L V8)
• 2002-2003 Chevrolet Avalanche 2500 (8.1L V8)

Features

• Short-tube performance header designed to increase low and mid-range power
• 409 stainless steel 16-gauge mandrel-bent tubing for improved flow
• Heavy-duty laser-cut port flanges resist warping and leaks
• Direct bolt-on installation with OEM-style connections - no welding needed
• Premium exhaust gaskets and all hardware included
• 50-state emissions legal; meets EPA & CARB requirements
• Lowers engine operating temperature by improving exhaust scavenging
• Backed by a lifetime limited warranty for durability and peace of mind

Specifications

• Brand: Gibson Performance Exhaust
• Part Number: GP131S
• Type: Performance Shorty Header (stainless steel)
• Material: 409 stainless steel, 16-gauge
• Primary Tube Diameter: ~1.75"
• Collector Outlet: OE style flange to stock crossover pipe
• Installation: Direct replacement for stock exhaust manifolds
• Emissions: 50-state legal (EPA & CARB compliant)

Included Components

• 2x Stainless shorty header pieces
• 2x Premium exhaust gaskets
• Bolts/studs and installation hardware

Product Description

The Gibson GP131S Performance Header is a direct-fit stainless steel header engineered for heavy-duty GM trucks and SUVs equipped with the 8.1 L V8 engine from 2001 through 2003. Designed to replace restrictive factory exhaust manifolds, this shorty header uses mandrel-bent 409 stainless steel tubing and heavy-duty laser-cut flanges that improve exhaust flow, help reduce engine temperature, and enhance both low and mid-range horsepower and torque without requiring modifications or welding to the factory crossover pipe. :contentReference[oaicite:0]{index=0}

Installation is straightforward - the GP131S bolts directly onto the engine using OEM-style connections and includes premium gaskets and all necessary hardware. Like other Gibson Performance Headers, it's designed to be 50-state emissions legal and meets both EPA and CARB requirements, meaning it can be used on public roads without affecting the vehicle's factory warranty. Drivers will notice improved throttle response, smoother engine breathing, and a slight increase in usable engine output thanks to the enhanced exhaust scavenging and reduced backpressure.

This header fits a range of GM heavy-duty pickup trucks and SUVs - including Chevrolet Silverado 2500HD/3500, GMC Sierra 2500HD/3500, Suburban 2500, Yukon XL 2500, and Avalanche 2500 - all powered by the 8.1 L V8 engine with automatic transmission. Its durable stainless construction and lifetime limited warranty make it a solid upgrade for owners looking to unlock additional performance and efficiency from their big block V8.