Do I need new fasteners to install this gasket?

Header bolts are reusable if they're in good condition. Check yours for stripped threads or corrosion before assembly — if the bolt holes are damaged, you'll want fresh hardware to avoid leaks.

Should I apply sealant to the gasket before bolting it down?

Aluminum gaskets seal through compression at the flange joint — additional sealant is not required and can actually create mess during disassembly later. Clean both surfaces with a wire brush or gasket scraper, install dry, then torque bolts evenly.

Can I reuse the gasket if I remove the header again?

One installation cycle is the safe limit. Once compressed and heat-cycled, aluminum gaskets lose their seal integrity. Use a fresh gasket if you pull the header a second time.