Twin Power 17-Up M8 with 4.25 Big Bore Kit 4.25in Head/Base Gasket Kit .030-.014 MLS
Why this price?
$90.99 is MSRP, the lowest price TwinPower lets us list it at. Additionally, Pro members get $15.47 back on this part.
$90.99 − $15.47 = $75.52
Special Order
This part is still available to order. Once you place your order, we’ll submit it directly to TwinPower, and they’ll ship it straight to you.
Delivery times can vary depending on the brand, so we can’t guarantee an exact arrival date. What we can guarantee is that we’ll stay on top of your order, monitor its progress, and keep you updated until it reaches your door.
Special-order items are typically not kept in stock by most retailers. By ordering through us, your order is placed directly with TwinPower, assuring you get the part as quickly as possible.
Want to get an estimated delivery timeframe before ordering? Contact us through our contact page, and we’ll be happy to find out for you.
Not sure it fits? Read our tips.
Fitment tips
Fitment can come down to more than year, make and model. Sometimes the sub-model decides, so start with the fitment table below.
- Drive type. If your car is all-wheel drive, make sure the part is for all-wheel drive, not rear-wheel drive.
- Engine size. For engine parts, make sure the engine size on the product matches your engine.
- Transmission. Manual and automatic cars often take different parts.
- Body style. Sedan or hatch, two-door or four-door, cab and bed length on trucks.
Manufacturer data can sometimes have imperfections. Still not sure? We are happy to help.
Send us a message and we will confirm the fit.
Couldn't load pickup availability
Cylinder Head and Base Gasket Kits for 124" and 128", oil-cooled or water-cooled models, with 4.25" Big Bore Cylinders. This is a strictly bolt-on kit, as the special gaskets eliminate the need to weld and modify oil or water passages. Gasket kits are available with either .030" or .040" thick gaskets . The Cylinders are offered in a factory-style black texture finish with highlighted fins. Cast-iron liners ensure strength, durability and quiet operation.
- Multi-Layer Steel construction for excellent heat and pressure resistance
- Thickness range .030 -.014 to fine-tune compression and gasket stack
- Sized specifically 4.25" big bore M8 applications
- Made in USA
This Part Fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2018-2020 | Harley-Davidson | FLDE Deluxe 107 | Base |
| 2018-2019 | Harley-Davidson | FLFB Fat Boy 107 | Base |
| 2025-2026 | Harley-Davidson | FLFB Fat Boy 117 | Base |
| 2018-2024 | Harley-Davidson | FLFBS Fat Boy 114 | Base |
| 2021 | Harley-Davidson | FLH Electra Glide Revival | Base |
| 2018-2021 | Harley-Davidson | FLHC Heritage Classic 107 | Base |
| 2025-2026 | Harley-Davidson | FLHC Heritage Classic 117 | Base |
| 2018-2024 | Harley-Davidson | FLHCS Heritage Classic 114 | Base |
| 2023 | Harley-Davidson | FLHFB Electra Glide Highway King | Base |
| 2017-2022 | Harley-Davidson | FLHR Road King | Base |
| 2017-2025 | Harley-Davidson | FLHRXS Road King Special | Base |
| 2019-2022 | Harley-Davidson | FLHT Electra Glide Standard | Base |
| 2017-2019 | Harley-Davidson | FLHTCU Electra Glide Ultra Classic | Base |
| 2017-2021,2023-2025 | Harley-Davidson | FLHTCUTG Tri Glide Ultra | Base |
| 2020-2022 | Harley-Davidson | FLHTCUTGSE CVO Tri Glide | Base |
| 2017-2024 | Harley-Davidson | FLHTK Ultra Limited | Base |
| 2017-2019 | Harley-Davidson | FLHTKL Ultra Limited Low | Base |
| 2017-2021 | Harley-Davidson | FLHTKSE CVO Limited | Base |
| 2017-2026 | Harley-Davidson | FLHX Street Glide | Base |
| 2017-2023 | Harley-Davidson | FLHXS Street Glide Special | Base |
| 2017-2026 | Harley-Davidson | FLHXSE CVO Street Glide | Base |
| 2022-2023 | Harley-Davidson | FLHXST Street Glide ST | Base |
| 2025 | Harley-Davidson | FLHXU Street Glide Ultra | Base |
| 2024 | Harley-Davidson | FLI Hydra-Glide Revival | Base |
| 2017-2025 | Harley-Davidson | FLRT Freewheeler | Base |
| 2018-2021 | Harley-Davidson | FLSB Sport Glide 107 | Base |
| 2018-2021 | Harley-Davidson | FLSL Softail Slim 107 | Base |
| 2025 | Harley-Davidson | FLSTFI Fat Boy Gray Ghost | Base |
| 2020-2024 | Harley-Davidson | FLTRK Road Glide Limited | Base |
| 2022-2023 | Harley-Davidson | FLTRKSE CVO Road Glide Limited | Base |
| 2023-2026 | Harley-Davidson | FLTRT Road Glide 3 | Base |
| 2017-2019 | Harley-Davidson | FLTRU Road Glide Ultra | Base |
| 2017-2026 | Harley-Davidson | FLTRX Road Glide | Base |
| 2017-2023 | Harley-Davidson | FLTRXS Road Glide Special | Base |
| 2018-2025 | Harley-Davidson | FLTRXSE CVO Road Glide | Base |
| 2022-2023 | Harley-Davidson | FLTRXST Road Glide ST | Base |
| 2024-2026 | Harley-Davidson | FLTRXSTSE CVO Road Glide ST | Base |
| 2018-2020 | Harley-Davidson | FXBB Street Bob 107 | Base |
| 2025-2026 | Harley-Davidson | FXBB Street Bob 117 | Base |
| 2021-2024 | Harley-Davidson | FXBBS Street Bob 114 | Base |
| 2018-2019 | Harley-Davidson | FXBR Breakout 107 | Base |
| 2023-2026 | Harley-Davidson | FXBR Breakout 117 | Base |
| 2018-2020 | Harley-Davidson | FXBRS Breakout 114 | Base |
| 2019-2020 | Harley-Davidson | FXDRS FXDR 114 | Base |
| 2018-2019 | Harley-Davidson | FXFB Fat Bob 107 | Base |
| 2018-2023 | Harley-Davidson | FXFBS Fat Bob 114 | Base |
| 2018-2020 | Harley-Davidson | FXLR Low Rider 107 | Base |
| 2020-2021 | Harley-Davidson | FXLRS Low Rider S 114 | Base |
| 2022-2026 | Harley-Davidson | FXLRS Low Rider S 117 | Base |
| 2022-2026 | Harley-Davidson | FXLRST Low Rider ST 117 | Base |
| 2022 | Harley-Davidson | FXRST Low Rider El Diablo 117 | Base |
| 2020-2024 | Harley-Davidson | FXST Softail Standard 107 | Base |