Do I need new bolts when I install this gasket?

Reuse your factory header bolts if they're in good condition. If any are stripped, corroded, or bent, grab new ones in the same size and specification as your originals.

Should I clean the header and cylinder head before installing the new gasket?

Yes. Wire-brush or scrape away old gasket material and carbon buildup from both surfaces. A clean, flat seating surface prevents leaks.

Will this work with aftermarket headers?

This gasket is cut for factory header bolt patterns. If you're running an aftermarket header with a different bolt layout, verify the hole spacing matches before ordering.