Blessed Performance has the Full-Race F-150 & Raptor 3.5L EcoBoost Formline® Exhaust Manifold Hardware Kit.
You know the sound. A tick or chirp on cold start that fades as the engine warms up. Maybe an exhaust smell in the engine bay, or boost that isn't quite what it used to be. That's the classic 3.5L EcoBoost exhaust manifold leak. Everyone blames the manifolds themselves, and they're half right. The other half is the studs holding them on.
The OEM studs are carbon alloy steel with an upper service temperature of just 370 to 425°C (698 to 797°F), a limit the EcoBoost pushes past every day. The factory nuts don't help either: they lock by deforming the threads, which is why they're one-time-use parts. Add years of heat cycling and the coatings burn off, clamp force bleeds away, and fatigue builds until stud heads snap off and the chirping starts. More bolt holes won't fix that, and neither will installing the same hardware that just failed.
This Full-Race Formline® Exhaust Manifold Hardware Kit fixes it at the source. The FR studs are machined from A286, a high-nickel superalloy developed for jet engines that holds its strength and clamp load up to around 650°C (1202°F), hundreds of degrees past the point where the factory studs have already gone soft. Instead of a nut that locks by crushing itself onto the stud and tearing up the threads every time it’s installed or removed, ours have a rolled anti-rotation thread built in. The joint locks mechanically so nothing gets deformed, and the included anti-seize is all it takes to protect the threads for the next time the manifolds come off.