Do I need to replace the gasket if I'm just removing and reinstalling my header?

Yes. Gaskets compress during initial installation and lose sealing ability once removed. A fresh gasket prevents exhaust leaks at the manifold joint.

Can I reuse the old fasteners when bolting the header down?

Check your header bolts for damage or corrosion before reuse. If they're intact, they'll work fine—just torque them evenly to avoid warping the new gasket.

Does this gasket need sealant applied before installation?

No additional sealant required. Aluminum gaskets seal through compression alone when fasteners are properly tightened. Over-applying sealant can actually prevent proper seating.