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Michigan Motorsports

Michigan Motorsports LS Multi-Layer Steel (MLS) Header Manifold Exhaust Gasket | Direct Replacement for GM 12617944 | High-Performance Seal for LS1 LS2 LS3 LS6 LQ4 LQ9 4.8 5.3 5.7 6.0 6.2 Engines

  • Based on 207 reviews
Condition: New
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Availability: In Stock.
Fulfilled by Amazon
Arrives Monday, Nov 3
Order within 18 hours and 57 minutes
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Features

  • Perfect Fitment for LS Engines: Specifically designed to fit GM LS-series engines, including LS1, LS2, LS3, LS6, LS7 and LQ-series platforms.
  • High-Performance Multi-Layer Steel (MLS) Construction: Designed for maximum durability and superior sealing, preventing exhaust leaks in high-temperature and high-performance applications.
  • Direct OEM Replacement: Precision-engineered to match GM OEM specifications for an easy, hassle-free installation. No modifications or special tools required, making it perfect for DIY enthusiasts and professionals alike.
  • Enhanced Sealing Performance: Multi-Layer construction provides exceptional resistance to blowouts and warping, even under high-stress conditions. Eliminates commons issues like exhaust leaks and noise.
  • Essential for LS Swaps, Performance Builds, and Maintenance: A must-have for engine rebuilds, header installations, and LS swap projects, offering superior sealing performance for high-output applications.

Brand: Michigan Motorsports


Material: Multi-Layer Steel


Item Thickness: 0.04 Inches


Color: Silver


Manufacturer: Michigan Motorsports


Manufacturer: ‎Michigan Motorsports


Brand: ‎Michigan Motorsports


Item Weight: ‎6.4 ounces


Product Dimensions: ‎17.5 x 3.5 x 0.5 inches


Item model number: ‎12617944


Is Discontinued By Manufacturer: ‎No


Manufacturer Part Number: ‎J3400-02


Date First Available: November 15, 2017


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Nov 3

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

  • Klarna Financing
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  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

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Top Amazon Reviews

    • Get these over the fiber style gaskets that burn out over time
Got these when I had to pull my heads, they fit perfectly, didn’t leak a bit when torqued to spec, were easy to install and super high quality! Got 30k miles on them already and they’re still holding strong. Best value for the money out there
Reviewed in the United States on July 22, 2025 by Ethan McCoy
    • Doesn’t leak at all
These or the Delco ones are the ones to buy anything else and you’ll be doing the job again. Bought quite a few of these work with both oem manifolds and aftermarket headers. If you’re buying them probably be extracting broken bolts as well, welder and nuts about the best way anything else your wasting your time. ... show more
Reviewed in the United States on June 29, 2025 by Levi Cates
    • Great
Work great as they are intended. Good value
Reviewed in the United States on April 19, 2025 by Awill
    • Get what you pay for!
Great parts as always. And easy to install if engine is out. Not bad if it’s in.
Reviewed in the United States on August 5, 2025 by Young’s Automotive Farm
    • Proper gasket for these engines.
Packed well and fit perfectly. Also this is the correct style gasket for these engines. Not like the crap ones the auto parts stores keep on stock to sell and charge more for…
Reviewed in the United States on April 19, 2025 by melissa ridella
    • Great for Lontubes No leaks!
Amazing and have had no leaks with longtube headers! Buy these instead id the paper ones! These are a lot more reliable!
Reviewed in the United States on December 10, 2024 by Alexis
    • Does the job!
Not quite OEM quality but did seal the surfaces. No leaks!
Reviewed in the United States on January 25, 2025 by Mark Kirby
    • Great product Great price and would definitely purchase again 👍 👍
Great product Great price and would definitely purchase again 👍 👍
Reviewed in the United States on January 3, 2025 by Fernando Solis

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