What is the difference between the .030" and .040" gasket options?

The thickness of the gasket affects the compression ratio of your engine. Thicker gaskets, like the .040" option, will slightly lower the compression, while thinner gaskets, like the .030" head gaskets included here, will slightly increase it. Your engine builder will typically recommend the correct thickness based on your build specifications.

Do I need any special tools to install these gaskets?

While this is a bolt-on kit, proper installation of engine components requires specific tools and knowledge. Always refer to the manufacturer's installation instructions for any specialized tool requirements or torque specifications.

What does MLS stand for in MLS head gaskets?

MLS stands for Multi-Layer Steel. These gaskets are constructed from multiple layers of steel with a special coating, offering excellent sealing capabilities and durability, especially in high-performance applications like big bore engines.

Twin Power 17-Up M8 with 4.25 Big Bore Kit 4.25in Head/Base Gasket Kit .030-.014 MLS

Specifications

Brand: TwinPower
Part #: 042124
UPC: 887337402819

Twin Power 17-Up M8 with 4.25 Big Bore Kit 4.25in Head/Base Gasket Kit .030-.014 MLS

Name: Twin Power 17-Up M8 with 4.25 Big Bore Kit 4.25in Head/Base Gasket Kit .030-.014 MLS
Brand: TwinPower
SKU: twinpower-twin-power-17-up-m8-with-4-25-big-bore-kit-4-25in-head-base-gasket-kit-t14-610337
Price: 93.17 USD
Availability: BackOrder

$93.17

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Key Features

Fits 2017+ Harley-Davidson M8 models with 4.25in Big Bore cylinders.
Includes .030 inch MLS head gaskets and .014 inch base gaskets.
Designed for 124" and 128" M8 engines, both oil-cooled and water-cooled.
Strictly bolt-on kit, eliminating the need to weld or modify oil/water passages.
Features cast-iron liners for strength, durability, and quiet operation.
Made in USA.

Secure CheckoutFast Shipping631-982-0042

Will this fit your vehicle?

Product Details

When you're upgrading your M8 engine to a 4.25-inch big bore, getting the right gaskets is crucial for a solid seal. This kit from Twin Power is specifically made for those 124" and 128" M8 builds, whether your engine is oil-cooled or water-cooled.

What's great about this kit is that it's a strictly bolt-on affair. The special gaskets included here mean you won't have to mess with welding or modifying your oil or water passages, which can be a real headache. You get .030-inch thick MLS head gaskets and .014-inch thick base gaskets, designed to handle the increased demands of a big bore setup. These gaskets are made in the USA and feature cast-iron liners for strength and quiet operation.

This gasket kit fits a wide range of Harley-Davidson models from 2017 and up, including popular bikes like the Road King, Street Glide, and Fat Bob, when equipped with 4.25" big bore cylinders.