Designed for Gen III and Gen IV LS-based engines, the FAST Big Mouth 102mm Throttle Body provides a significant increase in airflow for high-performance and boosted applications. CNC-machined from billet aluminum, this cable-driven throttle body features an increased blade thickness to eliminate deflection under high manifold pressure, a common failure point in forced induction setups.

The offset blade pivot improves throttle response and provides a smoother opening transition, while the beefed-up linkage and dual throttle spring mechanism ensure consistent, reliable control. This unit comes complete with the Throttle Position Sensor (TPS) and Idle Air Control (IAC) motor for a straightforward installation on 102mm-compatible intake manifolds.

• Bore Size: 102mm
• Material: CNC-machined billet aluminum
• Drive Type: Cable driven
• Engine Compatibility: GM Gen III and Gen IV LS engines
• Includes: Integrated TPS and IAC sensors
• Reinforced blade prevents deflection in boosted applications
• Dual spring mechanism for precise throttle return

Designed for LS1, LS2, and LS6 engines, the FAST LSXR 102mm Intake Manifold Kit (146302B-KIT) provides a significant increase in airflow and throttle response over factory setups. This kit pairs the high-flow LSXR manifold with the Big Mouth 102mm Throttle Body to maximize induction capacity.

The LSXR manifold is engineered from a high-strength polymer that effectively resists heat soak, maintaining cooler intake air temperatures for more consistent power delivery. To ensure precise control, the included Big Mouth throttle body features a billet throttle blade that eliminates deflection under high vacuum or boost conditions.

• Direct fitment for LS1, LS2, and LS6 engine platforms
• 102mm Big Mouth throttle body with billet blade for increased durability
• Advanced polymer manifold construction reduces heat transfer
• Stealth black finish for a clean engine bay aesthetic
• Includes all necessary components for the 102mm conversion
• Manufacturer Part Number: 146302B-KIT

Fits select 2003-2018 Chrysler 300/Aspen, Dodge Challenger/Charger/Durango/Magnum/Ram, Jeep Commander/Grand Cherokee, and Ram 1500/2500/3500 models.

The FAST Big Mouth LT 87mm Throttle Body is an engineered solution for Chrysler HEMI owners seeking improved throttle control and durability, particularly in boosted applications. Constructed from premium billet aluminum, this unit features increased throttle blade thickness to eliminate the deflection common in standard throttle bodies under high pressure. Performance is further refined through an offset blade pivot that enhances operating smoothness and throttle response.

Designed for reliability, the Big Mouth LT utilizes a beefed-up linkage and a dual throttle spring mechanism to ensure consistent, total throttle control. The 87mm bore provides significant airflow advantages over stock components, all while maintaining a durable black-wrinkle powder coat finish for superior corrosion resistance and a clean engine bay aesthetic.

• Bore Diameter: 87mm
• Material: CNC-machined billet aluminum
• Finish: Black-wrinkle powder coating
• Improved blade thickness to resist deflection under boost
• Offset blade pivot for faster response
• Heavy-duty linkage and dual spring mechanism
• Manufacturer Part Number: 54088

Designed for maximum power in both boosted and naturally aspirated applications, the FAST LSXHR 103mm Intake Manifold is a tunnel-ram style polymer manifold optimized for GM LS cathedral port engines (LS1, LS2, and LS6). Engineered to withstand continuous boost pressures up to 45psi, this manifold features a lightweight polymer construction that resists power-robbing heat soak compared to traditional aluminum designs.

The LSXHR features a modular design with interchangeable velocity stacks, allowing tuners to find the ideal runner length for their specific RPM range. The compound fuel injector angle is specifically positioned to improve fuel atomization for better drivability and power production. For versatile packaging, the reversible top plate allows for either forward- or firewall-facing throttle body mounting. Each runner includes two integrated nitrous nozzle bosses for a clean direct-port installation.

• Manufacturer Part Number: 146303
• Engine Compatibility: GM LS1, LS2, LS6 (Cathedral Port)
• Throttle Body Opening: 103mm (Port matchable up to 105mm)
• Boost Rating: Up to 45psi continuous pressure
• RPM Range: Optimized for 5,000 to 7,500 RPM
• Runner Design: Includes tall removable velocity stacks (medium and short sold separately)
• Construction: High-strength, heat-resistant polymer
• Included Hardware: Custom fuel rails and installation hardware

Fits select GM Gen IV LS engines including LS3, LS7, L76, L77, and L99 applications.

The FAST Big Mouth 102mm Electronic Throttle Body (54104) is a clean-sheet design engineered specifically for high-performance drive-by-wire (DBW) applications. Featuring a full 102mm bore, this unit significantly increases airflow over stock components, making it an ideal match for FAST manifolds or high-flow aftermarket intake systems. Unlike modified stock units, this throttle body utilizes a proprietary high-torque motor for superior response times and a steady blade position even in high-boost environments.

Built for long-term reliability, it incorporates a dual return spring and a precision non-contact Throttle Position Sensor (TPS). The satin black anodized finish provides a durable, professional aesthetic for any engine bay.

• 102mm bore diameter for maximum airflow and reduced restriction
• Designed for GM Gen IV LS factory ECUs and aftermarket systems like Edelbrock ProFlo4+
• High-torque motor prevents blade flutter under boost
• Non-contact TPS and dual return springs for increased reliability
• Clean-sheet design with no reused stock components
• Satin black anodized finish
• Manufacturer Part Number: 54104

Optimized for high-performance GM LS-based engines, the FAST LSX Big Mouth 102mm Throttle Body (MPN 54102) provides the increased airflow required for high-horsepower naturally aspirated and forced induction builds. This throttle body is engineered to solve common blade-flex issues by using a thicker blade design that eliminates deflection under high vacuum or boost conditions.

The Big Mouth series features a unique offset blade pivot, which facilitates a smoother transition for incoming air compared to standard designs. To ensure consistent throttle response and longevity, FAST has reinforced the linkage and spring mechanism, providing a more robust and reliable feel during performance driving.

• 102mm bore diameter for maximum airflow capacity
• Increased blade thickness prevents bending or deflection
• Smoother offset blade pivot reduces intake turbulence
• Reinforced linkage and heavy-duty spring mechanism
• Precision-machined billet construction
• Manufacturer Part Number: 54102

Fits select 1999-2019 GM vehicles including Chevrolet Silverado, Tahoe, Suburban, GMC Sierra, Yukon, and Cadillac Escalade. This FAST LSX Intake Manifold (54039B) is engineered to maximize airflow on LS-based engines, featuring a high-flow 92mm inlet and a durable black finish. Its multi-piece modular design simplifies access for porting and internal maintenance.

• Inlet Diameter: 92mm
• Finish: Black
• Manufacturer Part Number: 54039B
• Compatible with FAST Billet Fuel Rails (54023)
• Optimized for FAST Throttle Bodies (54092 and 54090)

Built for long-term serviceability, this manifold supports individual replacement parts, including the upper shell (54039BUS) and lower shell (54039BLS).

Ensure a reliable, leak-free connection between your manifold and cylinder heads with these FAST replacement intake port seals. Specifically engineered for the FAST LSX 92mm intake manifold, these gaskets restore vacuum integrity and prevent unmetered air from entering the combustion chamber.

Designed for professional-grade sealing, this set provides a precise fit when mating the 92mm LSX manifold to LS1, LS2, or LS6 cylinder heads. They are essential for any maintenance or engine build involving the removal of the intake to ensure consistent performance and idle quality.

• Specifically for FAST LSX 92mm intake manifolds
• Fits GM LS1, LS2, and LS6 cylinder heads
• Engineered for a precise, reliable seal to prevent vacuum leaks
• Set includes required port seals for a complete manifold installation
• Manufacturer Part Number: 54009-8

Ensure your EFI system receives precise intake data with the FAST Air Temperature Sensor (307004). This sensor is a direct replacement component specifically engineered for use with FAST EZ Fuel and EZ Fuel + Ignition throttle body systems.

By monitoring incoming air temperature, this sensor provides the critical data your ECU needs to accurately calculate air density. This ensures optimal fueling and ignition timing adjustments for improved engine efficiency and performance. It is built to original specifications for a reliable connection and long service life.

• Direct replacement for manufacturer part number 307004
• Specifically designed for FAST EZ Fuel and EZ Fuel + Ignition throttle bodies
• Provides essential temperature data for accurate ECU air-density calculations
• Durable construction for consistent performance in high-heat environments
• Factory-style connector for a secure installation

Fits select 2003-2018 Chrysler, Dodge, Jeep, and Ram models with the 6.4L New Hemi engine. This FAST XFI Fuel Injector Harness is engineered to provide a secure, high-integrity connection between your XFI ECU and the fuel injectors, ensuring precise signal delivery for optimized engine management.

While designed for the modern Hemi architecture, this harness offers the flexibility required for custom builds. It can be re-pinned to accommodate unique firing orders or reterminated for different injector connector styles, making it a versatile solution for specialized engine swaps and performance tuning.

• Directly connects XFI ECU to fuel injectors
• Engineered for Chrysler New Hemi 5.7L, 6.1L, and 6.4L applications
• Re-pinnable design allows for custom firing orders
• Can be reterminated for various injector connector types
• Manufacturer Part Number: 301208

Fits select 2003-2018 Chrysler, Dodge, Jeep, and Ram vehicles equipped with 5.7L or 6.1L Hemi engines. This FAST XFI Main Harness is the central nervous system for your EFI setup, designed to reliably connect your XFI ECU to essential engine sensors, ignition devices, and peripheral modules.

Engineered for professional-grade integration, this harness facilitates seamless communication between the ECU and high-performance components such as digital dashes, EGT modules, and other optional accessories. Built using high-quality terminals, seals, and connectors, it ensures a secure, weather-resistant connection that stands up to the heat and vibration of a high-performance engine bay. Whether you are performing a modern Hemi swap or upgrading an existing EFI system, this harness provides the plug-and-play reliability needed for precise engine management.

• Product Line: XFI Main Harness
• Manufacturer Part Number: 301104
• Engine Compatibility: Modern Hemi 5.7L and 6.1L
• System Compatibility: Works with FAST XFI ECUs
• Construction: High-quality automotive-grade seals and connectors
• Connectivity: Supports digital dashes and EGT modules

The FAST Tailpipe Mount O2 Sensor Kit provides a reliable, non-permanent solution for oxygen sensor testing and air-fuel ratio tuning. This tool is specifically designed for automotive technicians and tuners who need to monitor exhaust data without welding a permanent sensor bung into the exhaust system. The assembly simply slides into the tailpipe, allowing for quick installation and removal during dyno sessions or diagnostic testing.

Constructed from high-grade stainless steel for durability and corrosion resistance, the mount features a threaded port to accept standard oxygen sensors. To ensure the vehicle's aesthetics are maintained, FAST includes a specialized rubber cover that prevents the mounting hardware from scratching or marring polished exhaust tips.

• Replaces the need for welding a temporary O2 bung
• Durable stainless steel construction for repeat use
• Slides directly into the tailpipe for rapid setup
• Integrated rubber cover protects polished or chrome exhaust tips
• Engineered for accurate air-fuel ratio monitoring during testing
• Manufacturer Part Number: 170620

Fits select 1999-2019 GM vehicles, including Chevrolet Silverado/Tahoe, GMC Sierra/Yukon, Cadillac Escalade, and Hummer H2/H3 (4.8L / 5.3L / 6.0L).

The FAST LSXRt 102mm Intake Manifold for GM truck engines provides significant bolt-on performance gains without sacrificing the bottom-end drivability required for towing and daily use. This manifold is engineered specifically for 4.8L, 5.3L, and 6.0L platforms, featuring standard design runners that are optimized for mild street applications. The 102mm throttle body opening allows for maximum airflow to support increased horsepower and torque across the RPM range.

• 102mm throttle body bore for improved induction
• Durable black finish for a custom engine bay look
• Standard design runners maintain low-end torque and drivability
• Direct bolt-on installation for LS-based truck engines
• Manufacturer Part Number: 146602B

The FAST LSXR 102mm Intake Manifold (146302B) for Gen III LS engines is engineered to maximize airflow and horsepower while resisting the performance-robbing heat soak common with aluminum manifolds. Fits select 1999-2019 GM vehicles (Chevrolet, GMC, Cadillac, Buick, and Hummer) equipped with LS-based engines.

Constructed from a high-strength, advanced polymer, this manifold offers significant weight savings and improved thermal characteristics over aftermarket metal alternatives. The 102mm throttle bore is designed for high-performance street and racing applications, providing the massive intake capacity needed for modified engines. This black version offers a stealthy appearance while maintaining the legendary durability and bolt-on fitment of the LSX series.

• Bore Size: 102mm throttle body opening
• Material: Advanced heat-dissipating polymer
• Finish: Black
• Performance: Increased strength and lighter weight than aluminum intakes
• MPN: 146302B

Fits LS1, LS6, and LS7 cylinder heads equipped with a FAST LSXR 102mm intake manifold.

Ensure a reliable, leak-free connection between your manifold and cylinder heads with these FAST replacement intake port seals. Specifically engineered for the LSXR 102mm series, these gaskets prevent vacuum leaks that can lead to inconsistent idle, lean conditions, and lost performance. These seals provide a precise fit for high-performance induction systems, making them essential for new manifold installations or routine engine maintenance on LS-based engines.

• Designed specifically for FAST LSXR 102mm intake manifolds
• Compatible with LS1, LS6, and LS7 cylinder head ports
• Helps maintain airtight integrity for consistent fueling and performance
• Durable elastomer construction resistant to heat and chemicals
• Manufacturer Part Number: 146203-8

The FAST LSXR 102mm Intake Manifold (MPN 146202B) is engineered specifically for LS7 engines, providing a high-performance alternative to both factory and aftermarket aluminum intakes. Constructed from a specialized, high-strength polymer material, this manifold offers a significant weight reduction compared to aluminum while providing superior heat dissipation. This material choice minimizes heat soak, ensuring a cooler, denser air charge for improved combustion.

Designed with a 102mm inlet to accommodate larger throttle bodies, the LSXR series optimizes airflow volume and velocity. The black finish provides a modern, stealthy appearance under the hood without compromising the structural integrity required for high-vacuum or forced induction environments.

• Inlet Diameter: 102mm
• Material: Advanced high-strength polymer
• Finish: Black
• MPN: 146202B
• Engine Compatibility: LS7 (7.0L)
• Features: Modular runner design and improved heat-dissipating characteristics

Vehicle Fitment:

Fits select 2007-2017 Cadillac Escalade, Chevrolet Camaro/Corvette/Silverado/SS/Suburban/Tahoe, GMC Sierra/Yukon, Hummer H2, and Pontiac G8 models with rectangular port engines.

The FAST LSXHR FAST-RAM Intake Manifold is the industry’s first polymer tunnel ram-style manifold designed for maximum performance in both naturally aspirated and high-boost applications. Rated for up to 45psi of continuous pressure, this manifold is engineered to withstand the rigors of forced induction while virtually eliminating the power-robbing heat soak common in aluminum alternatives. The polymer construction provides high strength and a lightweight profile, while the tunnel ram design has shown average gains of 30 horsepower between 5,000 and 7,500 RPM.

Equipped with removable velocity stacks of various lengths, racers can fine-tune the intake runner combination to optimize the power band for their specific application. The manifold features a reversible top for flexible forward or firewall-facing throttle body mounting and includes two nitrous nozzle bosses per runner for clean direct-port installations. A compound fuel injector angle ensures ideal spray atomization for improved drivability and peak power production.

• Manufacturer Part Number: 146106
• Throttle Body Opening: 103mm (port-matchable to 105mm)
• Pressure Rating: 45psi continuous (boost-ready)
• Material: High-strength, heat-resistant polymer
• Configuration: Tunnel ram-style with removable internal stacks
• Compatibility: Gen III/IV LS Rectangular Port heads
• Installation Features: Reversible plenum top and dual nitrous bosses per runner

Fits select 2008-2017 Chevrolet Camaro, Corvette, and SS, and 2008-2009 Pontiac G8 models with rectangular port cylinder heads.

The FAST LSXR 102mm Intake Manifold (146102B) is engineered to provide superior airflow for performance LS engines. Constructed from a high-strength, advanced polymer material, this manifold offers significant advantages over aluminum alternatives, including reduced weight and improved heat dissipation to prevent heat soak. This black-finish LSXR series manifold features a 102mm throttle body opening, optimized to support the high airflow demands of modified rectangular port engines.

• Manufacturer Part Number: 146102B
• Throttle Body Opening: 102mm
• Port Style: Rectangular Port
• Material: Advanced High-Strength Polymer
• Finish: Black
• Modular design for easier porting and customization
• Includes necessary hardware for installation

Ensure consistent fuel delivery and eliminate pressure drops with the FAST LSXR / LSXRT Billet Fuel Rail Kit (146032B-KIT). Specifically engineered for use with FAST LSX, LSXR, and LSXRT intake manifolds, these rails feature a significantly larger internal diameter than factory components. This increased bore volume dampens fuel pressure pulses and provides a massive reservoir of fuel, ensuring your injectors never run dry during high-demand or wide-open-throttle conditions.

• Construction: CNC-machined from high-strength, lightweight billet aluminum for long-term durability.
• Finish: Performance black anodized finish for superior corrosion resistance and a show-quality engine bay appearance.
• System Stability: High-volume internal bore stabilizes fuel distribution across all cylinders for improved horsepower potential.
• Compatibility: Designed for FAST LSXR and LSXRT series intake manifolds.
• Part Number: 146032B-KIT.

Please note: This kit does not include installation hardware kits 146020-KIT or 146021-KIT, which may be required for specific plumbing configurations.

Ensure consistent fuel delivery for your high-performance LS engine with the FAST Billet Fuel Rail Kit. Specifically engineered for use with FAST LSX, LSXR, and LSXRT intake manifolds, these rails feature a significantly larger internal diameter than standard components. This increased volume provides a critical buffer to prevent injectors from running lean during high-demand cycles.

Beyond volume, the increased bore acts as a dampener for pressure pulses within the fuel system, promoting more even fuel distribution across all cylinders to support higher horsepower levels. CNC-machined from high-strength billet aluminum, these rails offer a lightweight yet durable solution for performance fueling requirements.

• Fits FAST LSX, LSXR, and LSXRT intake manifolds
• Large internal diameter increases fuel volume and dampens pressure pulses
• CNC-machined billet aluminum construction with a durable anodized finish
• Helps ensure even fuel distribution and prevents injector lean-out
• Manufacturer Part Number: 146027-KIT

Please note: This kit does not include installation kits 146020-KIT or 146021-KIT.

Fits select Chevrolet and GM LS3, L99, and L76 engines. The FAST LSXR OE Fuel Rail Injector Spacer Kit is a specialized hardware solution designed to adapt factory fuel rails to high-performance aftermarket manifolds. This kit provides the specific spacing required to maintain correct injector geometry and rail alignment when upgrading to 102mm intake systems.

• Allows the use of original equipment (OE) fuel rails with FAST LSXR 102mm intake manifolds.
• Compatible with FAST intake manifold part numbers 146102B, 146103B, and 146104B.
• Ensures proper injector seating to prevent vacuum or fuel leaks at the manifold interface.
• Ideal for builders retaining the factory fuel system while increasing airflow capacity.
• Manufacturer Part Number: 146025-KIT

Maintain peak performance and vacuum integrity with the FAST LSXR and LSXRT Gen III Intake Manifold Seal Kit (MPN 146017). Designed specifically for FAST performance manifolds, this kit provides a complete set of replacement rubber components essential for a proper install or periodic maintenance.

Over time, heat cycles and fuel exposure can degrade intake seals, leading to performance-robbing vacuum leaks. This kit replaces those worn components with fresh seals that match the exact tolerances of the LSXR and LSXRT runner housings. It is an essential service item when porting, cleaning, or swapping your intake manifold.

• 8 Intake runner-to-cylinder head seals
• New injector O-rings for secure fuel rail sealing
• Lower shell rubber bumpers to prevent vibration and contact wear
• Vacuum port plugs for capping unused ports
• Engineered for FAST LSXR and LSXRT Gen III manifolds

Ensure a leak-free seal on your high-performance induction system with the FAST Replacement Inner Seal. This precision-engineered gasket is specifically designed to create a secure, airtight interface between the upper and lower shells of FAST 102mm LSXR and LSXRT intake manifolds.

As a critical component of the modular manifold assembly, this replacement seal (MPN 146005) prevents vacuum leaks and maintains consistent manifold pressure, which is vital for engine tuning and performance. Whether you are performing routine maintenance or reassembling your manifold after porting, using a fresh seal ensures optimal shell alignment and sealing integrity.

• Designed specifically for FAST 102mm LSXR and LSXRT intake manifolds
• Seals the critical junction between upper and lower manifold shells
• Helps prevent vacuum leaks and internal pressure loss
• Direct replacement for the original manifold shell gasket
• Manufacturer Part Number: 146005

Ensure a leak-free seal between your throttle body and intake manifold with the FAST 102mm O-Ring Seal. This precision-molded gasket is specifically engineered for use with FAST LSXR and LSXRT 102mm intake manifolds, providing a critical barrier against vacuum leaks that can cause erratic idling and performance issues.

• Designed specifically for FAST LSXR and LSXRT 102mm intake manifolds
• Ensures a reliable, airtight seal between the throttle body and manifold flange
• High-quality material construction for resistance to heat and chemicals
• Direct replacement for a worn or damaged factory gasket
• Manufacturer Part Number: 146004