The factory exhaust manifolds on your GMT800 Silverado, Sierra, or full-size SUV are one of the first restrictions holding back your LS engine. Speed Engineering's 1-7/8" longtube headers are a direct-fit, dyno-proven upgrade that frees up exhaust flow, improves throttle response, and delivers over 25 rear-wheel horsepower over stock. This is the race version — no air or EGR fittings.
Built from 304 natural stainless steel with mandrel-bent primary tubes, CNC-machined flanges, and full TIG-welded construction.
⚠️ Important Notes:
- Race version — no air or EGR fittings — not compatible with emissions equipment
- Silverado SS — these headers are NOT a direct fit to the Silverado SS dual inlet exhaust system. Speed Engineering's Y-pipe is a single outlet and will not connect directly to the Silverado SS factory dual inlet cat-back without modification
- 6.0L applications — most 6.0L trucks have a 2-into-1 factory exhaust system that the Y-pipe will NOT work with. Verify your factory exhaust configuration before purchasing. The X-pipe kit can work on 2-into-1 exhaust systems but will require fabrication for connection
- 4L80E transmission — bellhousing ears may need to be trimmed for proper clearance
- Earlier 2500 models may have fitment issues due to upper control arms being mounted on top of the chassis from previous years
Features:
- Full 1-7/8" Primary Tubes — Sized for maximum flow on 4.8L, 5.3L, and 6.0L LS applications
- 3" Collector — Optimized for strong low-to-mid RPM torque
- Mandrel Bent Tubing — Consistent tube diameter through every bend; no crimping, no restriction
- CNC Machined Flanges — Precision fit at the head and collector for a leak-free seal
- 304 Natural Stainless Steel Construction — Corrosion resistant, heat tolerant, and built to last
- Race Version — No Air or EGR Fittings
- Longtube Header Design — Maximum scavenging efficiency vs. shorty or mid-length headers
- Standard Graphite Manifold Gaskets Included
- Dyno Proven — 25+ RWHP gain on 4.8L, 5.3L, and 6.0L applications
- Compatible with 4.8L, 5.3L, and 6.0L LS V8 Engines
- V8 Engines Only
Vehicle Applications:
Chevrolet Silverado 1500 (2WD/4WD)
- 1999 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2000 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2001 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2002 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2003 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2004 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2005 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2006 Chevrolet Silverado 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
GMC Sierra 1500 (2WD/4WD)
- 1999 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2000 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2001 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2002 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2003 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2004 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2005 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
- 2006 GMC Sierra 1500 (2WD/4WD) — 4.8L/5.3L/6.0L
Chevrolet Tahoe (2WD/4WD)
- 1999 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2000 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2001 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2002 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2003 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2004 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2005 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
- 2006 Chevrolet Tahoe (2WD/4WD) — 4.8L/5.3L
GMC Yukon (2WD/4WD)
- 1999 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2000 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2001 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2002 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2003 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2004 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2005 GMC Yukon (2WD/4WD) — 4.8L/5.3L
- 2006 GMC Yukon (2WD/4WD) — 4.8L/5.3L
Cadillac Escalade (2WD/4WD)
- 2002 Cadillac Escalade (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2003 Cadillac Escalade (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2004 Cadillac Escalade (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2005 Cadillac Escalade (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2006 Cadillac Escalade (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
Cadillac Escalade EXT (2WD/4WD)
- 2002 Cadillac Escalade EXT (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2003 Cadillac Escalade EXT (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2004 Cadillac Escalade EXT (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2005 Cadillac Escalade EXT (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
- 2006 Cadillac Escalade EXT (2WD/4WD) — 6.0L ⚠️ Verify factory exhaust configuration — see 6.0L note above
Chevrolet Avalanche (2WD/4WD)
- 2002 Chevrolet Avalanche (2WD/4WD) — 5.3L
- 2003 Chevrolet Avalanche (2WD/4WD) — 5.3L
- 2004 Chevrolet Avalanche (2WD/4WD) — 5.3L
- 2005 Chevrolet Avalanche (2WD/4WD) — 5.3L
- 2006 Chevrolet Avalanche (2WD/4WD) — 5.3L
FAQ
How much horsepower do these headers add?
Speed Engineering's 1-7/8" longtube headers are dyno proven to add over 25 rear-wheel horsepower on 4.8L, 5.3L, and 6.0L LS equipped applications compared to stock exhaust manifolds.
What is the difference between the 1-3/4" and 1-7/8" headers for these trucks?
The primary tube diameter is the key difference. The 1-3/4" headers (25-1012) work well across a broad RPM range and are a strong choice for most street and mild performance builds. The 1-7/8" headers offer a step up in flow better suited for more aggressive builds with supporting modifications.
Do these headers have air or EGR fittings?
No. These are a race version and do not include air or EGR fittings. They are not compatible with emissions equipment.
Will these fit my Silverado SS?
These headers are not a direct fit to the Silverado SS factory dual inlet cat-back exhaust system. Speed Engineering's Y-pipe is a single outlet and will not connect directly to the Silverado SS dual inlet cat-back without modification.
Will a Y-pipe work on my 6.0L truck?
Most 6.0L trucks have a 2-into-1 factory exhaust system that the Y-pipe will NOT work with. Verify your factory exhaust configuration before purchasing. The X-pipe kit can be used on 2-into-1 exhaust systems but will require fabrication for the connection.
Will these fit with a 4L80E transmission?
These headers may require trimming of the bellhousing ears on 4L80E transmissions for proper clearance.
Will these fit on a 2500 model truck?
Earlier 2500 models may have fitment issues due to upper control arms being mounted on top of the chassis from previous years. Verify your specific application before ordering.
What engines are these headers compatible with?
These headers are compatible with GM LS V8 engines including 4.8L, 5.3L, and 6.0L found in 1999–2006 Silverado, Sierra, Tahoe, Yukon, Escalade, EXT, and Avalanche applications.
What material are these headers made from?
304 natural stainless steel with full TIG-welded construction and CNC-machined flanges.
Are gaskets included?
Yes. Standard graphite manifold gaskets are included with the headers.
Are these headers street legal?
No. These are race-only headers intended for closed-course competition use only. Installation on a street-driven vehicle may violate the Clean Air Act (42 U.S.C. 7522(a)(3)).
⚠️ Race Use Only: This product is manufactured and sold for installation on vehicles used solely for competition. Once installed, the vehicle may not be used, registered, or licensed for use on a public road or highway. Installation on a street-driven vehicle may violate the Clean Air Act 203(a)(3), 42 U.S.C. 7522(a)(3).
