This Holley EFI ECU mounting bracket lets you safely tuck an HP, Terminator X, or Terminator X Max ECU under the passenger seat of a Foxbody-era Mustang, keeping the engine bay clean and the ECU protected from heat.
Specifications:
- Compatible ECUs: HP EFI, Terminator X, Terminator X Max
- Vehicle Fitment: 1979-2004 Ford Mustang
- Mounting Location: Under the passenger seat, using stock seat tracks
- Material: Steel
- Color: Black
- Part Number: 554-157
Designed to fit under a stock passenger seat with stock seat tracks for these model years; modified or race seats may or may not accommodate the bracket and ECU assembly.
FAQ
Which Holley EFI ECUs fit this bracket?
It's designed for the HP EFI, Terminator X, and Terminator X Max ECUs.
Where does this bracket mount in the car?
It mounts under the stock passenger seat using the factory seat tracks.
Will this work with an aftermarket or race seat?
Not necessarily — it's designed around stock seat tracks, and a modified or race seat may not accommodate the bracket and ECU assembly.

