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    Sale!

    Holley LS1/6 (24x/1x) Engine Main Harness, Extended Length | 558-133

    Vendor: Holley EFI
    Part Number: 558-133
    Save $90
    Sale Price $715.95 Regular Price $805.95

    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.
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    This extended-length Holley engine main harness fits LS1/LS6 engines from 1997-2004 and interfaces with 24x crank and 1x cam sensors, letting installers mount the ECU inside the passenger compartment, away from the elements and easy to access.

    Specifications:

    • Engine platform: GM Gen III LS1/LS6 (1997-2004)
    • Crank/cam wheel type: 24x crank / 1x cam reluctor
    • Compatible ECUs: Dominator, HP EFI, Terminator X, and Terminator X Max
    • Length: 22" extended length for remote ECU mounting (roll bar, under passenger seat, etc.)
    • Injector connector type: Not specified in available Holley data — this is the engine main harness, not the injector harness
    • Throttle control (DBC/DBW): Not applicable/not specified — this harness does not include throttle body wiring
    • Transmission control: Not included — this is an engine-only main harness (no transmission control wiring)
    • Part Number: 558-133

    FAQ

    What ECUs is this harness compatible with?

    Dominator, HP EFI, Terminator X, and Terminator X Max ECUs.

    What crank/cam signal does it use?

    24x crank and 1x cam sensors, for LS1/LS6 engines built 1997-2004.

    Can I mount the ECU somewhere other than the engine bay?

    Yes — the 22" extended length lets you mount the ECU in the passenger compartment, on a roll bar, or under the passenger seat.

    Does this harness include transmission control?

    No — this is an engine-only main harness; transmission control wiring is not included.

    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.

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