✓ VERIFIED
Jan 16, 2020
Almost identical to OEM. Good fit. I did miss that they are sold as each and not as a pair. Small detail and my fault but it did slow my project down a bit.
COMETIC
SKU: 68-10256-030
Cometic Milwaukee-Eight Engine Gasket Kit 4.250" Bore 124ci .030" Head Gasket - Harley M8
$264.54
Free shipping on orders $99+ · Best value guarantee
affirm
From $22.04/mo with Affirm.
See if you prequalify
IN STOCK
— Ships within 24 hours
Free Shipping on orders $99+
Best Value Guarantee
30-Day Returns — see policy
Authorized Dealer — sourced direct
About Cometic
Cometic Gasket manufactures multi-layer steel head gaskets and complete gasket kits in Concord, Ohio. On a built V-twin running higher compression or a big-bore kit, the MLS head gasket is what keeps the top end sealed — which is why Cometic is the default spec on so many engine builds.
When it's time for a full engine rebuild or a performance upgrade on your Milwaukee-Eight, a complete and high-quality gasket kit is essential. This Cometic engine gasket kit is specifically designed for 124 cubic inch M8 engines with a 4.250" bore, providing all the necessary sealing components.
Why riders pick this
- Complete engine overhaul kit for 124ci Milwaukee-Eight
- Designed for 4.250" bore M8 engines
- .030" head gasket thickness for optimized builds
- All gaskets, seals, and O-rings included
- High-quality materials for performance applications
- Made in the USA
Engineered and manufactured in the USA, this Cometic gasket kit ensures precise fitment and lasting durability for your high-performance Milwaukee-Eight. It includes every gasket, seal, washer, and O-ring required for a comprehensive engine overhaul, from the top end to the bottom end. The .030" head gasket thickness is a critical detail for achieving specific compression ratios and optimizing piston-to-valve clearance in 124ci builds.
Precision Sealing for Big Bore M8 Builds
- Complete gasket kit for full engine rebuilds, no separate purchases needed
- Optimized for 4.250" bore and 124 cubic inch Milwaukee-Eight engines
- Features .030" head gasket thickness for specific build requirements
- All seals, washers, and O-rings are included for convenience
- High-quality materials designed to meet V-twin performance demands
- Manufactured in the United States for trusted quality and consistency
Build with Confidence
This Cometic engine gasket kit simplifies the process of sourcing sealing components for your M8 rebuild. Whether you're upgrading to a 124ci or performing a comprehensive refresh, these gaskets are engineered to provide a robust, leak-free seal across all critical engine surfaces. Always confirm the bore size, displacement, and head gasket thickness match your specific engine and piston combination before installation.
Specifications
- Brand: Cometic
- Manufacturer Part #: C10256-030
- Bore: 4.250 inch
- Displacement: 124 cubic inches
- Head Gasket Thickness: 0.030 inch
- Kit Dimensions: 8.75 in L × 7.5 in W × 2 in H
- Weight: 3 lbs
- Country of Origin: United States of America
Common questions
What's included in this Cometic engine gasket kit?
This is a complete kit, including every gasket, seal, washer, and O-ring needed for a full engine overhaul on Milwaukee-Eight engines with a 4.250" bore and 124 cubic inch displacement.
Is this a complete kit, or do I need other gaskets?
This is a comprehensive kit designed to cover all internal engine sealing surfaces for a full rebuild – no additional sealing components should be required.
Will this fit my Harley-Davidson Twin Cam engine?
No, this gasket kit is specifically engineered for Milwaukee-Eight (M8) engines with the specified bore and displacement. It will not fit Twin Cam or other Harley-Davidson engine platforms.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | Cometic |
| TYPE | Gaskets/Seals |
| SKU | 68-10256-030 |
| WEIGHT | 3.0 lb |
Please contact us to confirm fitment for your specific motorcycle, or check the product title for compatibility notes.
CUSTOMER REVIEWS
4.87
15 RATINGS
5★
13
4★
2
3★
0
2★
0
1★
0
✓ VERIFIED
Oct 18, 2021
Great seals and gaskets do the job once when you use quality gaskets
✓ VERIFIED
Sep 26, 2019
Seal good and I haven't had any issues..
✓ VERIFIED
Jun 27, 2025
It worked like it was suppose to, delivery was quick. <br />Pleased.
✓ VERIFIED
Dec 19, 2023
Just what I needed
Needed these when changing out intake manifold. They worked perfect for my ‘03 sporty.
✓ VERIFIED
Jun 12, 2023
Cometic from here on out
These seals are the only ones I'll use. others came close but, for me, these are best.
