An EFI system depends on a clean, constant voltage source, and grounds are just as important as the power side. This Holley harness kit includes the main harness, power harness, and injector harness needed to support your primary Ford V8 system.
Specifications:
- Harness Application: Ford
- Injector Connector: Jetronic/Minitimer (Bosch)
- Includes: Main power harness, universal MPFI main harness, Ford V8 injector harness, ignition adapter, tachometer input
- Product Type: Harness Kit
- Part Number: 558-508
Works with Dominator or 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
Does this harness kit include an ECU?
No, it's designed to pair with a Holley HP or Dominator ECU and a compatible oxygen sensor, both sold separately.
What injector style does it support?
Bosch (Jetronic/Minitimer) style injectors.
What's included?
Main power harness, universal MPFI main harness, Ford V8 injector harness, ignition adapter, and tachometer input.
Which ECUs is it compatible with?
Holley Dominator and HP EFI ECUs.

