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    • Proform Fits GM LS Engines with 3/8" Wide Flange 66826
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    Proform Fits GM LS Engines with 3/8" Wide Flange 66826

    Vendor: Proform
    Part Number: 66826
    Regular Price $39.95

    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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    Each PROFORM Grade 8 Header Bolt is permanently assembled with a pair of special washers. When the bolt is torqued to 28+ ft-lbs, the washers super-hardened external teeth bite into and grip the bottom of the bolt head and the top surface of the header. After being self-locked in this manner, any bolt-loosening rotation is blocked by a wedge-locking action created by the washers interfacing, matching cams. Its an uphill climb: vibration that might ordinarily loosen the bolt actually increases the wedge-locking tension, securing the bolt even more. Because this simple wedge-locking method uses tension instead of friction, contact with oil actually facilitates the wedge effect. When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.


    Proform Fits GM LS Engines with 3/8" Wide Flange 66826


    Specifications:

    Length 1.181 inch
    Diameter 8mm
    Feature/Benefit Wedge-Locking Technology Eliminates Constantly Re-Tightening Exhaust Collector Bolts; Blocks Bolt-Loosening Rotation caused by Vehicle Vibrations.
    Applications Fits GM LS Engines with 3/8-inch Wide Flange
    Category Header Bolts
    Color Nickel Plated
    Finish Nickel Plated
    Material Steel
    Part Type Header Bolts
    Description_ABR Header Bolts
    Description_SHO Locking Header Bolts
    Description_INV Header Bolts
    Description_INV Hex Head
    Description_INV M8 X 1.181in L
    Description_DEF Exhaust Header Bolt
    Description_ASC Wedge-Locking Header Bolts
    Description_ASC Hex Head
    Description_ASC M8 X 1.181in
    Description_ASC Chevy LS
    Description_ASC Nickel Plt
    Description_ASC 12 Pcs
    Description_LAB Wedge-Locking Header Bolts
    Description_LAB Hex Head
    Description_LAB M8 X 1.181in
    Description_LAB Chevy LS
    Description_LAB Nickel Plt
    Description_LAB 12 Pcs
    Description_DES Wedge-Locking Header Bolts
    Description_DES Hex Head
    Description_DES M8 X 1.181in
    Description_DES Chevy LS
    Description_DES Nickel Plt
    Description_DES 12 Pcs
    Description_EXT Engine Header Bolts
    Description_EXT Wedge-Locking Technology
    Description_EXT Hex Head Type
    Description_EXT M8 Thread X 1.181 Inch Long
    Description_EXT Shiny Nickel Plated Finish
    Description_EXT 12.9 Steel
    Description_EXT 12 Pcs in kit
    Description_EXT Fits GM LS Engines with 3/8" Wide Flange
    Description_MKT Each PROFORM Grade 8 Header Bolt is permanently assembled with a pair of special washers. When the bolt is torqued to 28+ ft-lbs, the washers super-hardened external teeth bite into and grip the bottom of the bolt head and the top surface of the header. After being self-locked in this manner, any bolt-loosening rotation is blocked by a wedge-locking action created by the washers interfacing, matching cams. Its an uphill climb: vibration that might ordinarily loosen the bolt actually increases the wedge-locking tension, securing the bolt even more. Because this simple wedge-locking method uses tension instead of friction, contact with oil actually facilitates the wedge effect. When changing headers, PROFORM Header Bolts can be untightened with a normal wrench, lubricated, and reused.


    This Part Fits:

    Year Make Model Submodel Notes
    2009 Chevrolet Avalanche
    2009 Chevrolet Avalanche
    1997 Chevrolet C1500
    1998 Chevrolet C1500
    1999 Chevrolet C1500
    1997 Chevrolet C1500 Suburban
    1998 Chevrolet C1500 Suburban
    1999 Chevrolet C1500 Suburban
    1997 Chevrolet C2500
    1998 Chevrolet C2500
    1999 Chevrolet C2500
    2000 Chevrolet C2500
    1997 Chevrolet C2500 Suburban
    1998 Chevrolet C2500 Suburban
    1999 Chevrolet C2500 Suburban
    1997 Chevrolet C35
    1998 Chevrolet C35
    1999 Chevrolet C35
    2000 Chevrolet C35
    1997 Chevrolet C3500
    1998 Chevrolet C3500
    1999 Chevrolet C3500
    2000 Chevrolet C3500
    1997 Chevrolet Camaro
    1998 Chevrolet Camaro
    1999 Chevrolet Camaro
    2000 Chevrolet Camaro
    1997 Chevrolet Cargo Van
    1998 Chevrolet Cargo Van
    1999 Chevrolet Cargo Van
    2000 Chevrolet Cargo Van
    2009 Chevrolet Cheyenne
    2009 Chevrolet Colorado
    1997 Chevrolet Corvette
    1998 Chevrolet Corvette
    1999 Chevrolet Corvette
    2000 Chevrolet Corvette
    2009 Chevrolet Corvette
    2009 Chevrolet Corvette
    1997 Chevrolet Express 1500
    1998 Chevrolet Express 1500
    1999 Chevrolet Express 1500
    2000 Chevrolet Express 1500
    2009 Chevrolet Express 1500
    1997 Chevrolet Express 2500
    1998 Chevrolet Express 2500
    1999 Chevrolet Express 2500
    2000 Chevrolet Express 2500
    2009 Chevrolet Express 2500
    2009 Chevrolet Express 2500
    1997 Chevrolet Express 3500
    1998 Chevrolet Express 3500
    1999 Chevrolet Express 3500
    2000 Chevrolet Express 3500
    2009 Chevrolet Express 3500
    2009 Chevrolet Express 3500
    2009 Chevrolet Express 4500
    2009 Chevrolet Express Cargo
    2009 Chevrolet Express Pasajeros
    2009 Chevrolet Express Pasajeros
    2009 Chevrolet Impala
    1997 Chevrolet K1500
    1998 Chevrolet K1500
    1999 Chevrolet K1500
    1997 Chevrolet K1500 Suburban
    1998 Chevrolet K1500 Suburban
    1999 Chevrolet K1500 Suburban
    1997 Chevrolet K2500
    1998 Chevrolet K2500
    1999 Chevrolet K2500
    2000 Chevrolet K2500
    1997 Chevrolet K2500 Suburban
    1998 Chevrolet K2500 Suburban
    1999 Chevrolet K2500 Suburban
    1997 Chevrolet K3500
    1998 Chevrolet K3500
    1999 Chevrolet K3500
    2000 Chevrolet K3500
    1999 Chevrolet L30
    2000 Chevrolet L30
    1997 Chevrolet P30
    1998 Chevrolet P30
    1999 Chevrolet P30
    2000 Chevrolet P30
    1997 Chevrolet Silverado
    1998 Chevrolet Silverado
    1999 Chevrolet Silverado
    1999 Chevrolet Silverado 1500
    1999 Chevrolet Silverado 1500
    2000 Chevrolet Silverado 1500
    2000 Chevrolet Silverado 1500
    2009 Chevrolet Silverado 1500
    2009 Chevrolet Silverado 1500
    2009 Chevrolet Silverado 1500
    2009 Chevrolet Silverado 1500
    1999 Chevrolet Silverado 2500
    1999 Chevrolet Silverado 2500
    2000 Chevrolet Silverado 2500
    2000 Chevrolet Silverado 2500
    2000 Chevrolet Silverado 2500
    2009 Chevrolet Silverado 2500
    2009 Chevrolet Silverado 2500
    2009 Chevrolet Silverado 2500 HD
    2009 Chevrolet Silverado 3500
    2009 Chevrolet Silverado 3500 HD
    2000 Chevrolet Sonora
    1997 Chevrolet Suburban 1500
    1998 Chevrolet Suburban 1500
    1999 Chevrolet Suburban 1500
    2000 Chevrolet Suburban 1500
    2000 Chevrolet Suburban 1500
    2009 Chevrolet Suburban 1500
    2009 Chevrolet Suburban 1500
    2000,2009 Chevrolet Suburban 2500
    1997 Chevrolet Tahoe
    1998 Chevrolet Tahoe
    1999 Chevrolet Tahoe
    2000 Chevrolet Tahoe
    2000 Chevrolet Tahoe
    2000 Chevrolet Tahoe
    2009 Chevrolet Tahoe
    2009 Chevrolet Tahoe
    2009 Chevrolet Tahoe
    2009 Chevrolet Tahoe
    2009 Chevrolet Trailblazer
    1997 Chevrolet W3500 Tiltmaster
    1998 Chevrolet W3500 Tiltmaster
    1999 Chevrolet W3500 Tiltmaster
    2000 Chevrolet W3500 Tiltmaster
    2009 Chevrolet W3500 Tiltmaster
    1997 Chevrolet W4500 Tiltmaster
    1998 Chevrolet W4500 Tiltmaster
    1999 Chevrolet W4500 Tiltmaster
    2000 Chevrolet W4500 Tiltmaster
    2009 Chevrolet W4500 Tiltmaster
    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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