SKU: HLY558-304
UPC: 090127666777
MPN: 558-304
The Holley HEI Ignition Harness (558-304) is an EFI wiring adapter designed to connect older GM small cap HEI distributors with modern Holley Avenger, HP, and Dominator EFI fuel injection systems. This ignition harness allows for retrofitting classic or vintage vehicles with contemporary fuel management technology while maintaining the original engine bay aesthetics. It is ideal for automotive enthusiasts looking to modernize their vehicles without sacrificing the classic look.
The adapter harness serves as the critical signal interface between the existing small cap HEI distributor and Holley's EFI platforms. It translates the original distributor's firing pattern into the digital input format required by the ECU, ensuring clean ignition trigger signals for optimal fuel injection timing and spark advance control. This design enhances drivability and starting reliability, making it a valuable addition for EFI conversions.
The 558-304 harness is particularly beneficial for enthusiasts performing EFI conversions on small block or big block Chevrolet engines equipped with original HEI ignition systems. Common applications include street rods, restorations, and performance builds where modern fuel management is desired while preserving the original engine configuration. This product eliminates the need for a complete distributor replacement, simplifying the upgrade process.
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