Do I need new bolts or studs to install these gaskets?

Gasket set only. Reuse your existing header bolts or studs if they're in good condition—no hardware included with this gasket pack.

Should I prep or clean the sealing surfaces before installation?

Yes. Scrape old gasket material and carbon from both the cylinder head and header mounting surfaces, then wipe clean with a shop rag. A dry, smooth surface ensures proper seal.

Can I reuse the old gasket or does this need to be replaced every time?

Replace it. Exhaust gaskets compress and lose their seal after removal. Install fresh gaskets every time you pull the headers off.