Skip to Product Info
    • 558-504.jpg
    • 271r960a-1.jpg
    • 271r960a-2.jpg
    Sale!

    Holley Universal V8 MPFI EFI Harness Kit, Ford/GM, Bosch Injector | 558-504

    Vendor: Holley EFI
    Part Number: 558-504
    Save $113
    Sale Price $899.95 Regular Price $1,012.95

    Available to order. In-stock orders typically ship in 1 to 2 business days.

    Not sure it fits your vehicle?
    Email sales@berryperformancesales.com with your year, make, model and engine, and we'll help you check fitment before you order.
    Fast Fulfillment: In-stock orders typically ship within 1 to 2 business days.
    Free Shipping on Orders Over $99 | Excludes freight shipments
    International Shipping Available: email sales@berryperformancesales.com for a quote.
    Payment & Security

    Secure, encrypted checkout. Card details go straight to the payment processor and are never stored by us.

    • Amazon
    • Amazon
    • American Express
    • Apple Pay
    • Diners Club
    • Discover
    • Google Pay
    • Mastercard
    • PayPal
    • Shop Pay
    • Venmo
    • Visa
    Share to:

    An EFI system depends on a clean, constant voltage source, and grounds are just as important as the power side. This universal Holley harness kit includes the main harness, power harness, and injector harness needed to support your primary V8 MPFI system.

    Specifications:

    • Harness Application: Ford, GM, Universal
    • Ignition Type: CD Ignition (No Timing Control)
    • Injector Connector: Jetronic/Minitimer (Bosch)
    • Includes: Main power harness, MPFI main harness, V8 injector harness
    • Product Type: Harness Kit
    • Part Number: 558-504

    Works with Dominator and HP ECUs. To complete your installation, add a Holley ECU and a compatible oxygen sensor.

    Compliance: This part is legal for sale and use on Racing Use Only Vehicles — competition vehicles that are not registered and never operated on the street. It is against the law to install this part on an Emissions Controlled Vehicle (1966-and-newer California-certified or 1968-and-newer federally certified vehicles).

    FAQ

    What vehicles is the 558-504 harness kit compatible with?

    It's a universal harness for Ford, GM, and other V8 MPFI applications.

    Does it include an ECU?

    No, pair it with a compatible Holley ECU and oxygen sensor, both sold separately.

    What ignition type does it support?

    CD ignition with no timing control.

    What's included?

    Main power harness, MPFI main harness, and V8 injector harness.

    Shipping Policy
    • Free shipping on orders over $99 (excludes freight shipments).
    • In-stock orders typically ship within 1 to 2 business days. Weekend and holiday orders are processed the next business day.
    • Orders ship from Defiance, Ohio and a nationwide network of warehouses and manufacturers.
    • Items showing an ETA are not in stock yet. ETAs come from the manufacturer and can change.
    • No P.O. Boxes. International orders need a shipping quote, so email us first.

    Read the full Shipping Policy

    Return Policy
    • 30-day return window from the ship date. Returns must be approved first; email sales@berryperformancesales.com with your order number.
    • Items must be unused, complete and in the original packaging.
    • A 20% restocking fee applies, and return shipping is paid by the buyer.
    • Not returnable: installed or modified parts, opened or used programmers and tuners, custom orders, Open Box, and Clearance or Final Sale items.
    • Damaged, defective or incorrect items must be reported within 48 hours of delivery with photos.

    Read the full Return Policy

    Disclaimer

    All products are sold for off-road use only unless otherwise specified. Buyer assumes all responsibility for installation and operation. Seller is not liable for any incidental, indirect, or consequential damages — including engine failure, labor costs, or vehicle downtime — resulting from the use of any product sold.

    By making a purchase from Berry Performance Sales, you acknowledge and agree to abide by the terms and conditions of these Policies.

    For any questions or concerns, please contact us — we’re always happy to help.

    Recently Viewed