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Doug's Headers D3373-R Replacement Header, 1-5/8 In, 02-07 Chevy Truck
Doug's Headers D3373-R Replacement Header, 1-5/8 In, 02-07 Chevy Truck

Doug's Headers D3373-R Replacement Header, 1-5/8 In, 02-07 Chevy Truck

Raw, Round Port Flange Style, 1-5/8" Primary Tube Diameter, Steel, Natural

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Doug's Headers D3373-R Replacement Header, 1-5/8 In, 02-07 Chevy Truck
Doug's Headers D3373-R Replacement Header, 1-5/8 In, 02-07 Chevy Truck
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We estimate this item will ship on or before November 26th.
Part # 447D3373R
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Important Messages:

  • This item ships directly from the manufacturer. It may take an additional 2 business days for Dougs Headers to ship this item.
  • Get FREE shipping when your order includes this item and exceeds $99! Ground shipping only in the contiguous US.
  • This item ships via Ground Shipping only. Expedited and Air shipping options are not available.


Flange Style:
Round Port
Primary Tube Diameter:
Material Type:
MFG. Part #:
Collector Diameter:
2-1/2 Inch
Hardware Included:
Gasket(s) Included:
Sold in Quantity:
GTIN Code:


Doug's 2/4 WD TRUCK HEADERS Long Tube Raw SteelHeader development and design is complex and requires a substantial amount of time and resources to do the job right! Many manufacturers are unwilling to make the commitment and instead offer compromised headers at lower prices. Doug's will not compromise performance, quality or fit to compete with inferior designs at cheap prices. Every Doug's header is tuned with the proper tube size and length to efficiently remove all the exhaust from each cylinder, reducing pumping losses resulting in a dramatic increases in horsepower and torque. Doug's headers are carefully developed on the vehicles they are intended to fit and are re-checked numerous times during the design and manufacturing process.

  • 3/8" thick flanges... no warping
  • CNC mandrel bent tubes... accurate fit & better flow
  • Precision formed long transition collectors and long tube design... reduces backpressure and increases higher RPM horsepower
  • Heavy 16 gauge tubing... longer life
  • Tubes are pre-polished to remove scratches and the header is left unfinished (raw steel) for individual customizing


2002-2005 Chevrolet Avalanche 1500 5.3L/323 V8
2006 Chevrolet Avalanche 1500 5.3L/325 V8
2002-2007 Chevrolet Silverado 1500 4.8L/294 V8
2002-2005 Chevrolet Silverado 1500 5.3L/323 V8
2006-2007 Chevrolet Silverado 1500 5.3L/325 V8
2002-2005 Chevrolet Silverado 2500 5.3L/323 V8
2006-2007 Chevrolet Silverado 2500 5.3L/325 V8
2006-2007 Chevrolet Silverado 3500 5.3L/325 V8
2002-2005 Chevrolet Suburban 1500 5.3L/323 V8
2006-2007 Chevrolet Suburban 1500 5.3L/325 V8
2002-2006 Chevrolet Tahoe 4.8L/294 V8
2002-2005 Chevrolet Tahoe 5.3L/323 V8
2006-2007 Chevrolet Tahoe 5.3L/325 V8
2002-2006 GMC Sierra 1500 4.8L/294 V8
2002-2005 GMC Sierra 1500 5.3L/323 V8
2006-2007 GMC Sierra 1500 5.3L/325 V8
2002-2005 GMC Yukon XL 1500 5.3L/323 V8
2006-2007 GMC Yukon XL 1500 5.3L/325 V8
2002-2006 GMC Yukon 4.8L/294 V8
2002-2005 GMC Yukon 5.3L/323 V8
2005-2007 GMC Yukon 5.3L/325 V8


  • Doug's Headers D3373-R 1 5/8" 4-Tube Manifold Replacement Header Chevrolet Truck 5.3L 02-07 Raw Steel
  • Shorty Design - Raw Steel
  • Collector: 2 1/2
  • Port Shape: SAP
  • Primary Tube: 1 5/8
  • 50-State Smog Legal header
  • emissions code: legal only for off-highway use (except in California or states that have adopted California emission standards)
  • with A/C
  • CARB Executive Order D-57-19
  • with Column Shift
  • with Floor Shifter
Some parts are not legal for use in California or other states with similar laws/regulations

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Q & A

  • Maintaining your headers is an important part of any hot rod. Pat gives some tips and demonstrates how well Purple Metal Polish works for keeping your headers looking great.
  • Wouldn't it be nice to get the best of both worlds out of your headers? Speedway Motors has solved that problem with our exclusive heat resistant Armor Hot Coating. Now you can keep that great look with longer life.
  • Pat shows that exhaust can make a difference on even your daily driver. Check out this video of Pat with the Hooker Muffler installed on his '03 Suburban.
  • Our Tru-Ram Exhaust Manifolds are one of our most popular items. Tim provides more details about them and gives you a great look at them.

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