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Holley EFI 558-506 - Ford Modular 4 Valve EFI Harness Kit

1999-2004 Ford Modular 4 Valve Harness Kit

This wiring harness interfaces a Holley EFI ECU to a 4V Ford Modular engine. It is meant to be used in conjunction with an injector harness, a coil harness, and ignition modules. Most stock sensors are used with this harness.
Availability: Call to check stock.
Shipping: Free Shipping* On Orders Over $99!
Pricing: $1,069.95

Free U.S. Continental Shipping


Harness Kit Includes: Main Power Harness, Ford Modular Main Harness, Ford V8 Injector Harness, Ford Modular 4V Coil Harness, Coil Drivers
Simple Installation
Can be used with HP or Dominator ECU's

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California Prop 65WARNING: Cancer & Reproductive Harm -


NOTICE: You will need to purchase an ECU and O2 Sensor to make this a complete kit. This kit is meant to be used in conjunction with an injector harness, a coil harness and ignition modules.
Software and firmware updates can be downloaded here for free.


  • 558-506
  • 558-506
  • 090127721384
  • Holley EFI
  • Call to check stock.
  • New

Shipping Information

  • Item Requires Shipping
  • 9.0 lbs.
  • W15.0000” x H5.0000” x L14.0000”
  • Free U.S. Continental Shipping
  • Free Shipping* On Orders Over $99!


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