Pro-Dash Harness Un-terminated IO

The HOLLEY Pro-Dash Harness Un-terminated IO (SKU HLY558-456) is a precision electronic control harness designed for builders and enthusiasts integrating Holley's advanced EFI systems into custom and modified vehicles. This un-terminated configuration gives you complete control over wire routing and final connector selection, making it ideal for engine swaps, chassis builds, and retrofit applications where OEM harnesses don't fit your specific layout.

Built to Holley's exacting standards, the Pro-Dash harness features quality copper conductors and insulation rated for under-dash and engine bay environments. The un-terminated configuration means all wire ends are bare, allowing you to solder or crimp custom connectors that match your dashboard gauge cluster, warning lights, and auxiliary circuits without waste or rework. This approach is favored by serious fabricators because it eliminates the guesswork of pre-terminated connectors that may not align with your specific instrumentation.

Pro builders, engine swap specialists, and EFI tuners rely on this harness for LS, LT, and traditional V8 conversions where dashboard integration is non-negotiable. Whether you're dropping a modern fuel-injected engine into a classic platform or optimizing wiring in a race car, this harness allows for a tailored installation that meets your design requirements.