Do I need new bolts or hardware to install this?

The gasket itself includes no fasteners. Reuse your factory header bolts — they'll seat properly against the aluminum face. If bolts are stripped or damaged, you'll need replacements before install.

Does this gasket need any prep or sealant before I bolt it down?

Aluminum gaskets work best dry. Clean both the header and manifold flange surfaces with a wire brush to remove old gasket material and carbon buildup, then install with factory bolts hand-tight first. Torque to spec once seated evenly.

What if my header is cracked or warped — will this gasket still seal?

A gasket can only seal if both surfaces are flat and intact. Inspect the header for cracks or warping before installing. A damaged header will defeat even a new gasket and cause a continued leak.