Air and Fuel› Fuel Injection Systems and Components - Electronic
Holley
2X4 TERMINATOR STEALTH MAIN HARNESS
SKU: H00E 558-121
Moderate — 2–4 hours
Description
Part #: 558-121
Introducing 2x4 Terminator Stealth EFI upgrade components. The wait is over. These upgrade components allow you to use your current Terminator Stealth EFI throttle body, install a new main harness, and slave throttle body, and you are finished. This upgrade is also perfect for anyone wanting to convert their 2x4 supercharged combo over to Electronic Fuel Injection!
Features:
- 2x4 Side Mount Stealth Throttle Bodies - Provide the great looks of a classic Holley 4150 Carburetor, without any of the hassles
- Multiple Color options allows for any Terminator Stealth EFI system to be upgraded to a 2x4
- Plug and Play Main Harness provides a clean finished appearance and allows for a quick install!
- Laptop Tuning is Required with this upgrade, we recommend taking your vehicle to a certified Holley EFI Tuner/Installer
MIA's Description
Fitment
Fitment Guaranteed
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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.
Available on iOS & Android
Specifications
| Brand | Holley |
| Part Number | H00E 558-121 |
| Weight | 2.85 lb |
Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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