Gator Fasteners EMBK66L5P Heavy Duty Exhaust Manifold Bolt Kit (2017-2025 6.6L Duramax)
Fits: Chevrolet • GMC
Diesel Dollars is Southern Diesel Supply's Loyalty Program. Purchasing with Us Earns you 1 Point for every 1 Dollar spent to use for future buys!
By ordering the Gator Fasteners EMBK66L5P Heavy Duty Exhaust Manifold Bolt Kit (2017-2025 6.6L Duramax) you will earn 110 DIESEL DOLLARS in your SDS Fuel Tank!
The Gator Fasteners EMBK66L5P is a heavy-duty exhaust manifold hardware kit for 2017-2025 Chevrolet Silverado and GMC Sierra 2500HD/3500HD trucks with the 6.6L L5P Duramax. It is made from Gator's HD220 alloy, rated at over 220,000 PSI tensile strength, with a black oxide finish. You buy it to keep the exhaust manifolds sealed through heat cycles without stretched hardware or leaks.
Fitment
Fits 2017-2025 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD trucks equipped with the 6.6L L5P Duramax diesel. Gator lists it as a direct replacement for the factory exhaust manifold studs on 2017-2025 Chevy/GMC 6.6L L5P Duramax engines. It is not listed for the earlier LB7, LLY, LBZ, LMM or LML engines. Verify fitment by VIN, or call us before you order.
Why this part
Exhaust manifold hardware lives with extreme exhaust temperatures, constant thermal cycling and a corrosive diesel exhaust environment. Over time that is what leads to stretched threads, manifold warping and exhaust leaks. Gator built this kit to hold up to it. The proprietary HD220 alloy has tensile strength exceeding 220,000 PSI, which Gator says significantly outperforms the standard grade 10.9, 12.9 and 8740 chromoly studs commonly used in the industry. The black oxide finish protects against rust, and the hardware is precision-machined for a direct fit and easy installation.
A sealed manifold matters on the L5P beyond the leak itself. On 2017-2019 trucks, exhaust leaks are listed as a possible cause of emissions-related faults to rule out during diagnosis. On 2024 and newer trucks, GM lists intake and exhaust leaks among the causes of DPF soot overload, which sets code P2463. Tight manifold hardware takes one variable out of that diagnosis.
The right hardware matters on repairs, too. GM TechLink bulletin 24-NA-253 covers exhaust rattles and leaks on some 2023 Silverado and Sierra 2500HD/3500HD trucks traced to incorrect bolts used in previous repairs, not a factory defect. When the manifold hardware comes off, put the correct parts back on.
What you get
- Gator Fasteners HD220 Heavy Duty Exhaust Manifold Stud Kit, part number EMBK66L5P
- Exhaust manifold hardware made from Gator's proprietary HD220 alloy
- Black oxide finish for rust and corrosion resistance
Specifications
- HD220 High-Strength Material – Proprietary alloy with over 220,000 PSI tensile strength, engineered for superior durability
- Exceptional Heat & Fatigue Resistance – Designed to withstand extreme exhaust temperatures and thermal cycling without stretching or failure
- Corrosion Resistant – Black oxide finish protects against rust and harsh diesel exhaust environments
- Precision Fit – Direct replacement for factory exhaust manifold studs on 2017–2025 Chevy/GMC 6.6L L5P Duramax engines
- Long-Lasting Performance – Provides a secure, reliable seal for your exhaust manifold, preventing leaks and failures
- Gator Fasteners Quality – Backed by our commitment to premium quality and reliability – Nothing Bites Like Gator
About Gator Fasteners
Gator Fasteners has built heavy-duty engine fasteners in Clermont, Florida, since 2017. The lineup stays focused on head studs, main studs, rod bolts and exhaust hardware for Cummins, Powerstroke and Duramax engines from the late 1980s through 2025. For the Duramax, that includes exhaust manifold stud and bolt kits and flexplate bolt kits.
Frequently asked questions
Is this a stud kit or a bolt kit?
Gator sells it as EMBK66L5P, and its description calls it the HD220 Heavy Duty Exhaust Manifold Stud Kit, a direct replacement for the factory exhaust manifold studs on the L5P. If you want the exact hardware and piece count confirmed before you pull the manifolds, call the shop.
How does HD220 compare to grade 12.9 hardware?
Gator rates HD220 at over 220,000 PSI tensile strength and says it significantly outperforms standard grade 10.9, 12.9 and 8740 chromoly studs.
Will it fit my 2011-2016 LML?
It is not listed for it. This kit is listed only for 2017-2025 Silverado and Sierra 2500HD/3500HD trucks with the 6.6L L5P Duramax.
Questions on fitment? Call the shop at the number in the header. We install everything we sell.
Diesel Dollars is Southern Diesel Supply's Loyalty Program. Purchasing with Us Earns you 1 Point for every 1 Dollar spent to use for future buys!
By ordering the Gator Fasteners EMBK66L5P Heavy Duty Exhaust Manifold Bolt Kit (2017-2025 6.6L Duramax) you will earn 110 DIESEL DOLLARS in your SDS Fuel Tank!