Order Status & Returns
Gift Cards
Help Center
1-800-345-4545
Vehicle Info NeededHOLLEYPART NUMBER: 510-558-486
558-486 M8 Service Harness for 6.86 in. and 12.3 in. Holley Pro Dashes
$14295
Ships on 11/09/2026
Lowest Price GuaranteeItems You Need
![16-Gauge Premium Automotive Wire Blue [50 ft.]](https://www.jegs.com/images/mini_200/500/555/555-10852.jpg)
![16-Gauge Premium Automotive Wire Yellow [50 ft.]](https://www.jegs.com/images/mini_200/500/555/555-10853.jpg)
![16-Gauge Premium Automotive Wire Orange [50 ft.]](https://www.jegs.com/images/mini_200/500/555/555-10854.jpg)
![16-Gauge Premium Automotive Wire Purple [50 ft.]](https://www.jegs.com/images/mini_200/500/555/555-10855.jpg)
![550-511-3PK Sniper 2 EFI Conversion w/Power Distribution Module (PDM) & Inline Fuel Pump Master Kit [Black]](https://www.jegs.com/images/mini_200/500/510/510-550-511-3pk.jpg)
HOLLEY
Part Number : 510-550-511-3PK
$1,99995
![550-511-3XX Sniper 2 EFI Conversion [Black]](https://www.jegs.com/images/mini_200/500/510/510-550-511-3xx.jpg)
![Under-Dash Creeper [40 in. Length]](https://www.jegs.com/images/mini_200/500/555/555-81153.jpg)
![Crimp Connector Kit [160 Pieces]](https://www.jegs.com/images/mini_200/500/555/555-10705.jpg)
![61-Piece Heat Shrink Tubing Kit [Black]](https://www.jegs.com/images/mini_200/500/555/555-10630.jpg)
![Colored Electrical Tape [5 pack]](https://www.jegs.com/images/mini_200/500/555/555-w549.jpg)
![Electrical Tape [3/4 in. x 60 ft.]](https://www.jegs.com/images/mini_200/500/555/555-w502.jpg)
![18-Gauge Premium Automotive Wire Red [100 ft.]](https://www.jegs.com/images/mini_200/500/555/555-11321.jpg)
![18-Gauge Premium Automotive Wire Black [100 ft.]](https://www.jegs.com/images/mini_200/500/555/555-11320.jpg)
![16-Gauge Premium Automotive Wire Black [50 ft.]](https://www.jegs.com/images/mini_200/500/555/555-10850.jpg)
![16-Gauge Premium Automotive Wire Red [50 ft.]](https://www.jegs.com/images/mini_200/500/555/555-10851.jpg)
M8 Harnesses
M8 Service HarnessReplacement Harness for:
- 6.86 in. Holley Pro Dash
- 12.3 in. Holley Pro Dash
This Holley 558-486 M8 Service Harness will get your EFI system back to functioning as it did before the original harness was lost or damaged.
Simple Plug & Play Wiring Harnesses
Holley EFI systems have been relied on by enthusiasts across the globe for increased power, fuel economy, and overall engine efficiency. A properly functioning EFI system begins with correct wiring, and these Holley harnesses can assist. Each wiring harness provides fast and easy installation for quick wiring solutions.
Part TypeInstrument Panel Wiring Harness
Product LineHolley Wiring Harnesses
BrandHOLLEY
Package Height3.3
Package Width6.5
Package Length6.65
Weight0.46 PG
Part CategoryPerformance Parts
Part FitmentSei Universal
Vendor Part Number558-486
Package Qty1
Package TypeEA
Some parts are not legal for use in California or other states with similar laws / regulations
