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Replacing exhaust header bolts might seem like a minor task, but using the correct hardware is crucial for a secure and leak-free exhaust system. Inferior or incorrect bolts can lead to premature failure, exhaust leaks, and potentially costly damage to your vehicle. Investing in high-quality replacement bolts ensures longevity and optimal performance for your automotive exhaust.
12PCS COMPLETE HEADER BOLT KIT. This set includes 12 premium exhaust manifold/header flange bolts with integrated flanged heads—no need for extra washers. Designed to meet JIS specifications for precise fit and secure installation.
Compatibility: Directly replaces OEM Part Number 551696. This header bolt kit is engineered for LS Series engines, including LS1, LS2, LS3, LS6, LSX, LM7, LR4, LQ4, LQ9, L33, LH6, L92, L76, L99, L96, L82, L83, L84, L86, L87, and LT1 models.
GRADE 10.9 HIGH-STRENGTH STEEL. Each bolt is manufactured from heavy-duty alloy steel with a Grade 10.9 rating—built to withstand extreme torque, vibration, and heat for long-lasting, secure performance.
ADVANCED DACROMET COATING. Coated with Dacromet for superior corrosion resistance in high-moisture, salt-spray, and high-heat environments. The eco-friendly coating prevents rust without the risk of hydrogen embrittlement.
IDEAL FOR LS SWAPS & REBUILDS. Perfect for engine swaps, performance upgrades, or replacing worn-out OEM hardware. Trusted by mechanics and DIYers for reliable exhaust manifold fastening on any LS project.
3/8"-16 x 1.00", 12 point head bolts for use with Small Block Chevrolet, Big Block Chevrolet, Small Block Ford, Small Block Chrysler and Big Block Chrysler thick flange header applications Heat treated Grade 8 bolts with black oxide finish 16 pieces
OEM Number: The OEM part numbers for our exhaust manifold bolts is 551696, can be used to replace lost or broken and worn out manifold bolts. Please check the OEM, brand, model, and year carefully in advance to avoid the product being unusable
Suitable Vehicles: Our exhaust bolts are compatible with GM 1997-2024 LS LT series engines, compatible with Chevrolet 1999-2015 Tahoe, 2015 Suburban, and more. Please refer to the details page for more specific information on the applicable models
Product Size: Our packet includes 12 exhaust manifold bolts with the size of 1.28*0.66*0.66''. The thread size is M8x1.25, threaded part is 0.98'' long and 0.30'' wide, the diameter of hexagonal head is 0.39'', please do careful check the size in advance
Enhanced Strength and Security: Featuring a reinforced construction, these LS header bolts keep a secure connection between the exhaust manifold and the engine block, minimizes vibrations of manifold avoid the problem of insufficient turbocharging
Premium Material: These LS exhaust manifold bolts are crafted from grade 10.9 carbon steel, have exceptional strength, not easy to deform and break. Remain steadfast when exposed to constant vibrations from machine operation, avoid dislodging or loosening
Compatible with all 1955-1998/99 Chevy Small Block Exhaust Headers with up to ½” Thick Flanges 265 283 305 307 327 350 383 400 (These do not fit oem manifolds)
Also Compatible with Pontiac Buick Oldsmobile 326 350 389 400 421 455 V8 Engines Using Exhaust Headers with up to ½” Thick Flanges (These do not fit oem manifolds)
These are High Grade 18-8 Stainless-Steel Steel 3/8-16x1” Bolts and Washers That will NOT rust or Corrode like the chrome or steel ones sold. These Use a 5/16” Allen Wrench/Socket
【Compatible with Chevrolet】 This exhaust manifold bolt is compatible with Chevrolet Avalanche 2007-2013; Avalanche 1500 2002-2006; Colorado 2010-2012; Corvette 2020-2023; Express 1500 2003-2012; Express 2500 2003-2020; Express 3500 2003-2020; Express...
【Compatible with GMC】 This exhaust manifold bolt is suitable for GMC Canyon 2009-2012; GMC Envoy 2003-2009; GMC Savana 1500 2003-2013; GMC Savana 2500 2003-2020; GMC Savana 3500 2003-2020; GMC SAVANA 4500 2010-2020; GMC SIERRA 1500 1999-2013; GMC...
【Compatible Models】 This exhaust manifold bolt is suitable for Buick Rainier 2004-2007; Cadillac CTS 2018-2019; Cadillac Escalade 2002-2014; Chrysler Town & Country 2008; Dodge Grand Caravan 2008-2010; Hummer H2 2003-2009; Hummer H3 2008-2010; Hummer...
【Material】 This exhaust manifold bolt is made of 10.9 grade stainless steel, ensuring its strength and durability, waterproof and rustproof properties, resistance to deformation and corrosion, and ability to withstand extreme weather. It is a...
【Package List】 You will receive 12 M8 x 1.25 x 30mm exhaust manifold bolts. Sufficient quantity to meet your daily needs
Premium Materials: This exhaust manifold bolt is made from top-grade carbon steel, this exhaust manifold bolt delivers exceptional tensile strength and durability. Engineered to endure high-temperature, high-pressure conditions (perfect for exhaust...
Anti-Slip Hexagonal Shape: The outer hex design offers superior grip, preventing slippage during install/removal to boost efficiency. Maintains strength and form under extreme heat, ideal for exhaust system’s high-temp parts.
Precision Machining: Advanced machining ensures high-thread precision, creating a tight fit to minimize leakage risks. Designed for easy install/removal with standard tools, simplifying maintenance.
Versatile Use: This bolt kit works with various automotive exhaust systems and other components needing high-strength fastening. Comes with 10 bolts + 10 nuts—ample quantity for multiple applications.
Complete Kit: Package includes 10 exhaust manifold bolts + 10 nuts. Nut size: 0.7" × 1.45"—everything needed for secure exhaust system assembly.
Last update on 2026-07-17 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Automotive Replacement Exhaust Header Bolts
Understanding Bolt Materials
Stainless Steel: Offers excellent corrosion resistance, making it ideal for harsh engine bay environments. It's durable and can withstand high temperatures.
High-Carbon Steel: Often heat-treated for increased strength and durability. While strong, it may be more susceptible to rust than stainless steel if not properly coated.
Alloy Steels: These can offer superior strength and heat resistance, often used in high-performance applications. Ensure they have appropriate coatings for corrosion protection.
Bolt Size and Thread Pitch
Diameter: Measure the original bolt or the hole in your manifold and gasket to determine the correct diameter. Common sizes include M6, M8, and M10.
Length: The bolt needs to be long enough to securely fasten the header or manifold to the cylinder head without bottoming out. Measure the thickness of the components being joined.
Thread Pitch: This refers to the spacing and size of the threads. Using the wrong thread pitch will prevent the bolt from engaging properly or stripping the threads in the cylinder head. Consult your vehicle's service manual for specifications.
Head Style and Strength Grade
Head Style: Common styles include hex head, flange head, and socket head. Flange heads offer a wider bearing surface, distributing pressure more evenly.
Strength Grade: Bolts are graded to indicate their tensile strength. Higher grades (e.g., Grade 8 or Class 10.9) are stronger and better suited for high-stress, high-temperature exhaust applications.
Frequently Asked Questions
Why do exhaust header bolts need to be replaced?
Exhaust header bolts are subjected to extreme heat cycles and vibrations, which can cause them to stretch, weaken, or break over time. Replacing them ensures a secure seal and prevents exhaust leaks.
Can I use regular hardware store bolts?
It's generally not recommended. Automotive exhaust header bolts are made from specialized materials designed to withstand high temperatures and corrosive environments. Regular bolts may fail prematurely under these conditions.
What is the difference between header bolts and manifold bolts?
While the terms are often used interchangeably, header bolts are specifically designed for aftermarket exhaust headers, which can have different mounting requirements. Manifold bolts are for OEM exhaust manifolds. Always check compatibility with your specific exhaust component.
How do I know what size bolts I need?
The best way is to consult your vehicle's service manual for the exact specifications. You can also measure the diameter and length of the existing bolts or the threaded holes in your cylinder head.
Do I need special washers?
Yes, it's often recommended to use hardened washers, especially with higher-grade bolts. These washers help distribute the load evenly and prevent the bolt head from damaging the surface of the exhaust component.
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