Horsepower, Inc
Horsepower is a performance-driven aftermarket brand specializing in high-flow throttle bodies and EFI components for Harley-Davidson Twin Cam engines. Known for Big Bore and Max Flow throttle body systems, the brand delivers increased airflow, sharper throttle response and measurable horsepower gains. Riders upgrading engines, intake systems or fuel delivery trust Horsepower for precision-machined components built to support serious performance and reliable tuning.
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Horsepower, Inc - HPI-51D6-16B - Big Bore Throttle Body - Black - 51 mm - Twin Cam
Horsepower, Inc
$784.95Horsepower, Inc - HPI-51D6-16B - Big Bore Throttle Body - Black - 51 mm - Twin CamFeaturesIncludes throttle body, CNC ported intake manifold, throttle cable bracket, intake flanges and sealsFlow...$784.95 -
Horsepower, Inc - HPI-58D6-18B - Max Flow™ Throttle Body - Black - Twin Cam - 58 mm
Horsepower, Inc
$884.95Horsepower, Inc - HPI-58D6-18B - Max Flow™ Throttle Body - Black - Twin Cam - 58 mmFeaturesCompletely replaces OEM throttle body and manifold; fully compatible with OEM componentsSpecifically...$884.95 -
Horsepower, Inc - HPI-58D1-18B - Max Flow™ Throttle Body - Black - Twin Cam - 58 mm
Horsepower, Inc
$884.95Horsepower, Inc - HPI-58D1-18B - Max Flow™ Throttle Body - Black - Twin Cam - 58 mmFeaturesCompletely replaces OEM throttle body and manifold; fully compatible with OEM componentsSpecifically...$884.95 -
Out of stock
Horsepower, Inc - HPI-58D1-76B - Max Flow™ Throttle Body - Black - Twin Cam - 58 mm
Horsepower, Inc
$884.95Horsepower, Inc - HPI-58D1-76B - Max Flow™ Throttle Body - Black - Twin Cam - 58 mmFeaturesCompletely replaces OEM throttle body and manifold; fully compatible with OEM componentsSpecifically...$884.95 -
Horsepower, Inc - HPI-51D1-16B - Big Bore Throttle Body - Black - 51 mm - Twin Cam
Horsepower, Inc
$784.95Horsepower, Inc - HPI-51D1-16B - Big Bore Throttle Body - Black - 51 mm - Twin CamFeaturesIncludes throttle body, CNC ported intake manifold, throttle cable bracket, intake flanges and sealsFlow...$784.95 -
Horsepower, Inc - HPI-55D6-18B - Big Bore Throttle Body - Black - 55 mm - Twin Cam
Horsepower, Inc
$784.95Horsepower, Inc - HPI-55D6-18B - Big Bore Throttle Body - Black - 55 mm - Twin CamFeaturesIncludes throttle body, CNC ported intake manifold, throttle cable bracket, intake flanges and sealsFlow...$784.95 -
Horsepower, Inc - HPI-55D1-18B - Big Bore Throttle Body - Black - 55 mm - Twin Cam
Horsepower, Inc
$784.95Horsepower, Inc - HPI-55D1-18B - Big Bore Throttle Body - Black - 55 mm - Twin CamFeaturesIncludes throttle body, CNC ported intake manifold, throttle cable bracket, intake flanges and sealsFlow...$784.95 -
Horsepower, Inc - HPI-IF-6L - Intake Flange Set - '06-'17 Twin Cam
Horsepower, Inc
$64.95Horsepower, Inc - HPI-IF-6L - Intake Flange Set - '06-'17 Twin Cam Features CNC-machined 6061 billet aluminum construction Will not crack or warp like some forged flanges Made in the...$64.95 -
Horsepower, Inc - HPI-D1NJ-1 - Fuel Injectors - 6.2 gm/sec - Fits 2002-2005 FLHT/FLHR/FLHX/FLTR, 2001-2005 FLST/FXST and 2004-2005 FXD
Horsepower, Inc
$285.95Horsepower, Inc - HPI-D1NJ-1 - Fuel Injectors - 6.2 gm/secFeaturesRecommended for "Big Inch" engines with large plenums (120 hp or greater)43% increase in flow over stock injectorsMade in the USASpecs$285.95 -
Horsepower, Inc - HPI-IF-6E - Intake Flange Set - '01-'05 Big Twin
Horsepower, Inc
$64.95Horsepower, Inc - HPI-IF-6E - Intake Flange Set - '01-'05 Big Twin Features CNC-machined 6061 billet aluminum construction Will not crack or warp like some forged flanges Made in the...$64.95 -
Horsepower, Inc - HPI-DPR-1 - Fuel Pressure Regulator - Fits 2002-2007 FLHT/ FLHR/FLTR; 1995-1998 Touring models w/ Magnetti Marelli EFI
Horsepower, Inc
$128.95Horsepower, Inc - HPI-DPR-1 - Fuel Pressure RegulatorFeaturesEngineered for a direct fit in most OEM fuel-injection applicationsDesigned for greater fuel deliveryMade in the USAReplacement Part for...$128.95 -
Horsepower, Inc - HPI-OC-1 - Oil Filter Mount - Polished - Fits 1999-2006 Twin Cam "A" motors (except 06 Dyna)
Horsepower, Inc
$169.95Horsepower, Inc - HPI-OC-1 - Oil Filter Mount - PolishedFeatures6061 billet aluminum construction with a polished finishOptimized oil passages flow almost 30% more efficiently than others on the...$169.95
Horsepower, Inc Motorcycle Parts – Big Bore Throttle Bodies, High-Flow EFI and Twin Cam Performance
Horsepower has established a strong reputation in the Harley-Davidson performance market by engineering throttle bodies and EFI components designed to maximize airflow efficiency and engine output. The brand’s Big Bore and Max Flow throttle bodies are precision-machined to provide increased air volume, smoother throttle response and proven horsepower gains for Twin Cam engines. These performance upgrades are ideal for big-inch builds, aggressive camshaft setups and high-performance intake systems.
Designed as direct-fit performance replacements, Horsepower throttle bodies are available in multiple bore sizes, including 51 mm, 55 mm and 58 mm, allowing riders and builders to properly match airflow to engine displacement and riding goals. Supporting EFI components such as fuel injectors, intake flanges, fuel pressure regulators and oil filter mounts help create a balanced and efficient fuel delivery system.
Whether building a street-focused Twin Cam or a high-output performance engine, Horsepower products are trusted for their machining accuracy, consistent fueling performance and compatibility with professional EFI tuning. With a strong focus on airflow optimization, durability and real-world power gains, Horsepower remains a top choice for riders looking to unlock the full performance potential of their Harley-Davidson motorcycle.