GMC Jimmy 1999-2001, Steel 4-2-1 Long-Tube Tri-Y Exhaust Headers with Adapters by Doug Thorley Headers®. Primary Tubing Diameter: 1.75". Collector Outlet Diameter: 2.5". Emissions: CARB compliant. Backed by over 50 years of knowledge and experience, Doug's headers are designed to outflow your stock exhaust manifolds by leaps and bounds. Tri-Y (or 4 into 2 into 1) style headers by design will increase the power of your motor across the widest RPM band possible. That is the beauty of the design, and that is why they are the best street header available. To make these headers last, Doug's built them using industry leading 14-gauge mild steel tubing with 3/8" thick flanges. To top all of that off, all of Doug's headers come beautifully ceramic coated to greatly reduce under-hood temperatures and protect the headers from the environment. All 100% American made, and backed by Doug's lifetime warranty of course! Unless otherwise noted, these headers are designed to fit the vehicle as it came from the manufacturer. This includes components like cylinder heads, chassis, steering, motor mounts, body mounts and bushings, etc. If your vehicle is using aftermarket components, parts from other applications, or custom altered parts, then it is the installer's responsibility to verify fitment. Doug's headers are designed to outflow your stock exhaust manifolds by leaps and bounds. Their headers will increase the power of your motor across the widest RPM band possible. That is the beauty of the design, and that is why they are the best street header available.
Fitment notes: This part is CARB compliant.
|Primary Diameter: 1.75"|
|Collector Diameter: 2.5"|
|Emissions: CARB compliant|
|Header Material: Steel|
|Header Style: 4:2:1 Long Tube Tri-Y Header|
|Finish: Silver Ceramic Coated|
|Weld Up: Yes, adapters must be welded to exhaust system|
|Primary Tube Diameter (in): 1-3/4"|
|Primary Tube Gauge: 14 Gauge|
|Collector Attachment: 3-Bolt Flange|
|Collector Diameter: 2-1/2"|
|Flange Thickness: 3/8"|
|Bolts and/or Studs Included: Yes|
|Gaskets Included: Yes|
|Reducers/Adapters Included: Yes|
|Y-Pipe (Crossover) Included: No|
|Quantity: Sold as a Pair|
|Warranty: Limited Lifetime to original purchaser|
- High quality at an affordable price
- Expertly made from premium materials
- Built to match your exact requirements
Doug's Long Tube Headers replace restrictive stock exhaust manifolds with long primary tubes designed to dramatically increase the flow of exhaust gasses, and reduce power robbing back pressure within the exhaust system. Allowing the engine to breathe more freely improves power and efficiency, making Doug's Long Tube Headers one of the most cost-effective modifications you can make to your vehicle.
The Long Tube Header is perfect for any high performance street or strip application. Each header is constructed from thick wall steel, and all come finished with Doug's beautiful ceramic coating for long-lasting performance.
For over 50 years, Doug Thorley Headers has been an innovator in the automotive aftermarket. Driven by a passion for performance and superior quality, they are committed to developing 100% American-made products that will reliably deliver maximum horsepower and torque. Doug Thorley Headers® has been pushing the limits of automotive technology since they first invented the Tri-Y header in 1958, and they do it all on American soil.