Additional Images

Holley EFI 558-504 - Universal V8 MPFI EFI HARNESS KIT

Universal V8 MPFI

An EFI system depends heavily on being supplied a clean and constant voltage source. The grounds of an electrical system are just as important as the power side. Our Holley EFI Harness Kit comes complete with the main harness, power harness and injector harness to support your primary system!
Availability: Call to check stock.
Shipping: Free Shipping* On Orders Over $99!
Pricing: $609.95

Free U.S. Continental Shipping


Harness Kit Includes; Main Power Harness, Universal MPFI Main Harness, v-8 Injector Harness
Simple installation
Works with HP or Dominator ECU's

California Proposition 65

California Prop 65WARNING: Cancer & Reproductive Harm -


NOTICE: You will need to purchase an ECU and O2 Sensor to make this a complete kit.


  • 558-504
  • 558-504
  • 090127721353
  • Holley EFI
  • Call to check stock.
  • New

Shipping Information

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

Customer Reviews

Comment Total Reviews (0)

Write the First Review!

You must login to post a review.

  • Have a question? Ask the Pros
  • 1-800-456-0211Mon-Fri - 8am-6pm CST
    Sat-Sun - Closed
  • Shop With Confidence We Proudly Accept: