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ECU & Engine Management
ECU & Engine Management — Standalone EFI and LS Swap Solutions Engine management is the brain of a modern fuel-injected powertrain. The ECU processes data from dozens of sensors, calculates optimal fuel delivery and ignition timing thousands of times per...
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MSD 2900
EFI, Atomic TBI & Fuel Pump, Master Kit - Atomic EFI Master Kit
"C.A.R.B. EO # D-722 applies to 1987 and...
Part TypeFuel Injection System£2,302.99 inc VAT£1,919.16 ex VAT -
Holley EFI 550-1063
Holley EFI Terminator X Max Stealth 4150 - GM LS Engines - Shiny
Not recommended for 4x4 applications with electronic transfer...
Part TypeFuel Injection System£2,884.99£2,770.99 inc VAT£2,309.16 ex VAT -
Holley EFI 550-1065
Holley EFI Terminator X Max Stealth 4150 - GM LS Engines - Gold
Not recommended for 4x4 applications with electronic transfer...
Part TypeFuel Injection System£2,884.99£2,770.99 inc VAT£2,309.16 ex VAT -
Holley EFI 550-1064
Holley EFI Terminator X Max Stealth 4150 - GM LS Engines - Black
Not recommended for 4x4 applications with electronic transfer...
Part TypeFuel Injection System£2,884.99£2,770.99 inc VAT£2,309.16 ex VAT -
Holley EFI 550-1028
Holley EFI Terminator X Max Stealth 4150 - GM LS Engines - Shiny
Not recommended for 4x4 applications with electronic transfer...
Part TypeFuel Injection System£2,884.99£2,770.99 inc VAT£2,309.16 ex VAT -
Holley EFI 550-1030
Holley EFI Terminator X Max Stealth 4150 - GM LS Engines - Gold
Not recommended for 4x4 applications with electronic transfer...
Part TypeFuel Injection System£2,884.99£2,770.99 inc VAT£2,309.16 ex VAT -
Holley EFI 550-1029
Holley EFI Terminator X Max Stealth 4150 - GM LS Engines - Black
Not recommended for 4x4 applications with electronic transfer...
Part TypeFuel Injection System£2,884.99£2,770.99 inc VAT£2,309.16 ex VAT -
Holley EFI 550-1081
TERMX STEALTH 4500 2X4 BLACK - Holley EFI Terminator X Stealth 2x4 4500 Kit - Black
Not for use with engines producing less than...
Part TypeFuel Injection System£3,835.99£3,709.99 inc VAT£3,091.66 ex VAT -
Holley EFI 550-1061
TERMX STEALTH 4150 4 INJ LS 58X BLACK - Holley EFI Terminator X Stealth GM LS 4150 - Black
58X Crank - 4 Injectors - 650 HP
Part TypeFuel Injection System£2,352.98£2,253.98 inc VAT£1,878.32 ex VAT -
Holley EFI 550-1021
Holley EFI Terminator X Stealth Kit - 4150 Flange - GM 24X
24X Crank - 4 Injectors - 650 HP
Part TypeFuel Injection System£2,352.98£2,253.98 inc VAT£1,878.32 ex VAT -
Holley EFI 550-1071
TERMINATOR X STEALTH 4500 8 INJ BLACK - Holley EFI Terminator X Stealth 4500 - Black
8 Injectors - 800-1500 HP
Part TypeFuel Injection System£2,986.99£2,864.99 inc VAT£2,387.49 ex VAT -
Holley EFI 550-1005
Holley EFI Terminator X Stealth 4150 - Black - 8 Injectors
8 Injectors - supports up to 1250hp (Forced...
Part TypeFuel Injection System£2,567.99£2,488.99 inc VAT£2,074.16 ex VAT -
Holley EFI 550-1002
Holley EFI Terminator X Stealth 4150
Part # 34-42 is required for a bolt-on...
Part TypeFuel Injection System£2,045.99£1,972.00 inc VAT£1,643.33 ex VAT -
Holley EFI 550-1215
Holley EFI Terminator X - 2015.5-2017 Ford Coyote w/ Ti-VCT
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£3,089.99£2,957.99 inc VAT£2,464.99 ex VAT -
Holley EFI 550-1214
Holley EFI Terminator X - 2015.5-2017 Ford Coyote w/ Ti-VCT
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£3,089.99£2,957.99 inc VAT£2,464.99 ex VAT -
Holley EFI 550-910
Holley EFI Terminator X - Gen IV 4.8/5.3/6.0 GM Truck Engines and LS2/LS3 - 58x Crank
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£1,534.99£1,502.99 inc VAT£1,252.49 ex VAT -
Holley EFI 550-905
Holley EFI Terminator X - Gen IV 4.8/5.3/6.0 GM Truck Engines and LS2/LS3 - 58x Crank
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£1,534.99£1,502.99 inc VAT£1,252.49 ex VAT -
Holley EFI 550-1225
Holley EFI Terminator X - 2007-2013+ HEMI Gen III Kit
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£1,994.99£1,924.99 inc VAT£1,604.16 ex VAT -
Holley EFI 550-1224
Holley EFI Terminator X - 2007-2013+ HEMI Gen III Kit
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£1,994.99£1,924.99 inc VAT£1,604.16 ex VAT -
Holley EFI 550-1223
Holley EFI Terminator X - 2003-2006 HEMI Gen III Kit
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£1,994.99£1,924.99 inc VAT£1,604.16 ex VAT -
Holley EFI 550-904
Holley Terminator X ECU Kit - Early GM Truck - 24X
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£1,534.99£1,502.99 inc VAT£1,252.49 ex VAT -
Holley EFI 550-1213
Holley EFI Terminator X - 2013-2015 Ford Coyote w/ Ti-VCT
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£3,089.99£2,957.99 inc VAT£2,464.99 ex VAT -
Holley EFI 550-1212
Holley EFI Terminator X - 2013-2015 Ford Coyote w/ Ti-VCT
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£3,089.99£2,957.99 inc VAT£2,464.99 ex VAT -
Holley EFI 550-1211
Holley EFI Terminator X - 2011-2012 Ford Coyote w/ Ti-VCT
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£3,089.99£2,957.99 inc VAT£2,464.99 ex VAT -
Holley EFI 550-1210
Holley EFI Terminator X - 2011-2012 Ford Coyote w/ Ti-VCT
Terminator X ECU's are designed to be mounted...
Part TypeFuel Injection System£3,089.99£2,957.99 inc VAT£2,464.99 ex VAT
ECU & Engine Management — Standalone EFI and LS Swap Solutions
Engine management is the brain of a modern fuel-injected powertrain. The ECU processes data from dozens of sensors, calculates optimal fuel delivery and ignition timing thousands of times per second, and adjusts in real time to maintain performance, efficiency, and engine protection across all operating conditions. Choosing the right engine management system — and ensuring it's correctly wired and calibrated — is one of the most consequential decisions in any performance build or engine swap project.
With over 200 engine management products from Holley EFI, Haltech, MSD, and related specialists, Billy's Speed Shop stocks a comprehensive range of ECUs, engine wiring harnesses, and control modules for everything from plug-and-play LS swap solutions to fully configurable standalone systems capable of managing the most complex race engine combinations.
Standalone EFI Systems — Complete Engine Management
Standalone EFI systems replace the factory engine management entirely, providing full user-configurable control over fuel delivery, ignition timing, launch control, boost control, and ancillary functions. The major advantage of a standalone system over a factory ECU is the ability to tune freely without dealer-level tools, integrate non-factory sensors and components, and expand the system's capabilities as the build evolves.
For LS swap applications, standalone systems eliminate the complexity of adapting a factory LS ECU to a non-factory vehicle — avoiding the need for security bypass modules, instrument cluster integration challenges, and the limitations of tuning a system that wasn't designed for aftermarket modification. A quality standalone ECU provides a clean, known starting point with full tuning capability from day one.
Engine Wiring Harnesses — Clean Installation
The engine wiring harness connects the ECU to every sensor, actuator, and control system on the engine. On LS swap and EFI conversion projects, a quality harness is the difference between a professionally executed installation with reliable long-term function and a problematic build where the wiring is a constant source of intermittent faults and troubleshooting. Our harness range includes pre-terminated, labelled harnesses designed for specific engine and ECU combinations, eliminating the time and risk associated with building a custom harness from scratch.
Engine Control Modules and Brackets
Factory LS ECUs — used in applications where a factory-based tune is preferred — require correct mounting solutions that protect the module from vibration, heat, and moisture. ECU mounting brackets position the module securely in a suitable location within the engine bay or interior, with appropriate ventilation and protection. Wiring harness extensions and bulkhead connectors facilitate clean harness routing through firewalls and between engine and interior.
EFI Conversion Kits
Complete EFI conversion kits provide everything needed to convert a carburetted engine to fuel injection in a single package — throttle body, ECU, harness, sensors, and fuel system components selected and matched for compatibility. These kits dramatically simplify what would otherwise be a complex multi-component sourcing exercise and are available in configurations suited to both traditional carburetted V8 engines and LS-based builds.



