T-56 Magnum Transmission Harness

The T-56 Magnum Transmission Harness by Holley is an essential wiring solution for builders integrating modern engine control systems with the legendary T-56 six-speed manual transmission. Designed for performance enthusiasts and professional fabricators tackling LS swaps, crate engine builds, and complete powertrain conversions, this harness bridges the gap between contemporary fuel injection management and traditional transmission architecture. Whether you're upgrading a classic muscle car or optimizing a street machine's drivability, the T-56 Magnum Transmission Harness provides the critical electrical backbone needed for seamless clutch operation and shift feel.

This Holley harness is engineered with precision-terminated connectors and gauge-optimized wiring to handle the demands of modern ECU communication with clutch hydraulics, shift solenoids, and transmission sensors. The compact assembly measures 9.3 x 4.15 x 12.5 inches and weighs just 0.78 lbs, allowing for flexible routing through tight engine bays and tunnel spaces common in retrofit applications. The harness integrates fully with Holley EFI systems and compatible standalone controllers, supporting real-time transmission data logging and adaptive shift programming that maximize both performance and reliability under demanding driving conditions.

This harness is ideal for anyone converting to a fuel-injected, computer-controlled engine platform while retaining or upgrading to the T-56 Magnum transmission for its proven durability and overdrive efficiency. Professional builders, restoration shops, and serious DIY fabricators benefit from Holley's plug-and-play connector design, which reduces wiring errors and installation time on complex builds. Compatibility with Holley Terminator X, HP EFI, and other modern engine management systems ensures your transmission electronics stay synchronized with fuel, ignition, and boost parameters for optimized shift logic and clutch engagement across the entire RPM range.