Do I need to replace the header bolts when I install this gasket?

Header bolts can be reused if they're in good condition, but inspect them during removal — any that are bent, stripped, or corroded should be replaced. New bolts are a cheap insurance policy on a fresh gasket seal.

What prep work is needed before I install the new gasket?

Clean both the header and cylinder head mating surfaces with a wire brush or scraper to remove old gasket material and carbon buildup. A clean surface ensures a solid seal — don't skip this step.

Will this fix an exhaust leak, or do I need to check the header itself?

A worn gasket is the most common cause of header leaks. If you're hearing exhaust noise near the engine bay, this gasket is your first replacement. If the leak persists after install, the header itself may be cracked or warped — inspect it during removal.