Do I need to clean the header and cylinder head surfaces before installing these gaskets?

Yes. Scrape off all old gasket material and carbon buildup from both mounting surfaces. A clean, flat surface is the only way these gaskets seal properly—any debris or residue will cause leaks immediately.

What bolts do I use to clamp the headers down?

The set includes the gaskets only. You'll need the factory header bolts from your vehicle—refer to your service manual for torque specs and bolt diameter. Have those on hand before you start.

Can I reuse these gaskets if I pull the headers off later?

No. Aluminum gaskets compress and conform to surface irregularities—once removed, they won't seal again. Plan on fresh gaskets every time you pull your headers.