Hooker BlackHeart Long Tube Headers - Stainless

1973-1974 GM K10 4WD Trucks with LS Swap, Tube Size 1-7/8", Collector 3", Natural Finish

Part # BH13326
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This product is engineered to facilitate the installation of a later model, emissions friendly engine into a vintage / classic vehicle.

See Emissions Details
Hooker Blackheart is pleased to announce the release of our new LS engine swap headers for the 1973-1974 Chevy K10 truck chassis. These headers are designed to increase engine performance and provide the best component and ground clearances available for this application. They can be used with all GM automatic transmissions, the venerable SM465 manual transmission, and NP203, NP205, NP208, and NP241 transfer cases. In addition, they feature 100% 304SS stainless steel construction, 3/8" thick flanges, and formed-merge collectors with one O2 bung in each of them.


  • Long-Tube LS Swap Headers for 1973-1974 K10 4WD Trucks
  • Use with Hooker BlackHeart Engine Swap Brackets BHS555, or WB130054
  • Compatible with factory transmission crossmembers and most GM automatic transmissions (TH350, TH400, 700R4, 4L60-4L70, 4L80E/4L85E, 6L80/6L90), and SM465 manual transmissions
  • Compatible with factory right-side-drop NP203, NP205, NP208, and NP241 transfer cases
  • Headers are constructed from lightweight 18-gauge 304 stainless steel with 3/8-inch waterjet cut flanges – for strength, durability, and corrosion protection
  • Choose from – BH13325 (LS swap with 1-3/4-inch primary tubes), or BH13326 (LS swap with 1-7/8-inch primary tubes)
  • Formed-merge collectors promote maximum flow velocity through the collectors – for maximum performance
  • O2 sensor bung included in each collector
  • 100% hand-welded construction for strength, longevity, and great looks
  • Tube geometry is designed for maximum component clearance and hassle-free installation
  • All hardware included
  • Manufacturer’s limited lifetime warranty

About Hooker BlackHeart

The BlackHeart team utilizes the latest technology and materials to design exhaust systems, engine swap kits, and mufflers for both import and domestic cars and trucks. Hooker BlackHeart is platform-engineered to provide superb performance, aesthetics, and fitment.

Bolt SizeM8 x 1.25 x 25mm
Brand Hooker BlackHeart
CARB (California) CompliantNo
Collector Diameter3.00 inch
Emission Code8
EngineGM Small Block Gen III/IV (LS Based)
Exhaust SeriesHooker BlackHeart
Header FinishNatural
Header StyleLong Tube
Material304 Stainless Steel
Primary Tube Dia.1-7/8 inch
Product TypeHeaders
Tube Material304 Stainless Steel
Type of ComponentHeaders
WarrantyLimited Lifetime Warranty
Part NumberBH13326

This product is engineered to facilitate the installation of a later model, emissions friendly engine into a vintage / classic vehicle. Federal guidelines indicate that an engine swap is allowable if one or more of the following conditions apply:

  • If there is a reasonable basis for knowing that emissions are not adversely affected as described in the EPA Tampering Policy dated November 23rd, 2020
  • The resulting vehicle is identical (with regard to all emissions related parts, engine design parameters and engine calibrations) to a certified configuration of the same or newer model year as the vehicle chassis
  • The vehicle is a uncontrolled vehicle - Vehicles that were manufactured before emission control regulations took effect are called uncontrolled vehicles. Aftermarket parts regulations and anti-tampering laws do not apply to these vehicles
  • An EO legal engine swap kit is utilized (such as a GM EROD)
  • The vehicle is being used for Competition Use Only - Racing Use Only Vehicles are vehicles that are used exclusively for competition that are not registered and that may never be used on the street

Consumers are responsible for complying with laws prohibiting tampering, and for ensuring that modified vehicles are operated in a manner that complies with applicable laws.

Motor vehicle emissions standards are intended to help achieve and maintain air quality goals that benefit human health and the environment. The U.S. Environmental Protection Agency, the California Air Resources Board, Environment Canada, and other regulatory agencies prohibit the operation of vehicles on public roads that violate applicable emissions standards. The alteration of certified production vehicles to modify, remove, or render inoperable emissions control hardware or software, known as "tampering" is prohibited by the U.S. Clean Air Act and other laws. Tampering with motor vehicles emissions control systems is punishable by substantial monetary penalties.

Holley is committed to performance parts that allow enthusiasts to modify their vehicles and meet emission requirements. The information provided here is intended to provide general guidance of interest to most consumers. This guidance may not apply to all vehicles or all situations. It is up to each consumer to evaluate his or her own situation and take the steps necessary to comply with applicable laws. The websites listed below have more information about regulations and policies pertaining to motor vehicle emissions. You should also check the regulations applicable to your local area.

EPA Website

CARB Website

Designed to be used with Hooker Blackheart BHS555 or WB130054 (LS) K10 engine mounting brackets. Can only be used with passenger-side-drop front axles and transfer cases. Collectors are designed to use double-slip coupler clamps for connection to an exhaust system (Hooker part number 41173HKR, or equivalent). Geometrically/functionally compatible with GM TH350, TH400, 700R4, 4L60-4L70, 4L80E/4L85E, 6L80/6L90 automatic, and SM465 manual transmissions. Depending on the transmission used, an aftermarket column linkage/cable kit, such as those offered by Lokar, may be required to provide column-shifted operation of your transmission. These headers do not possess a CARB Executive Order Exemption and are therefore not legal for sale or use on pollution-controlled motor vehicles
Limited Lifetime Warranty: See Details

*Free Shipping & Handling only offered to the contiguous US on orders over $100, excludes clearance parts and oversized packages.

Some parts are not legal for use in California or other states with similar regulations.