S&S Valve Spring Kit .585

Yes, this would be an excellent choice for your needs since this valve spring kit for the 2025 Harley Davidson FLFB Softail Fat Boy is designed to handle lifts up to .605". It'll work well with your setup.

It's really never a bad idea to upgrade the valve springs, especially since you're already that far into the engine! You'll never regret it, that's for sure. Plus, the S&S components are more durable than the stock springs anyway, so you can expect more accurate valve timing, easier (more consistent, really) tuning and better throttle response over the long term when using this spring kit.

Yes, you can use these springs with cams that have up to 0.650" of lift. They're far more durable than stock and, by many accounts, help quiet down valve noise, especially when running cams that are closer to stock lift. Either way, they're most certainly an improvement over the OEM Harley-Davidson valve springs!

While it's not required for every set of Harley-Davidson cams on the market, it's never a bad idea to to upgrade the valve springs anytime you're opening up valve lift. These valve springs are suitable for lifts up to 0.650" - so the 585C cams you're working with are well within the specification for these S&S engine valve springs to handle.

Yes, the valve guide seals are indeed included. And, as the 585C cams are indeed suitable for use with these valve springs. In fact, these particular springs can be used with any cam kit with up to a .650" lift.

S&S 510 gear drive cams don't require you to replace the stock valve springs as the lift is only .510" for that motor. If you want some springs to provide positive valve seating pressure while also allowing room for further modification up to .650" valve lift, the springs we have here are perfect for your needs. S&S valves include top collars, bottom collars, springs, shims and valve keepers and will install directly to the OEM valves on your 88" engine.