Do I need to clean or prep the header and cylinder head surfaces before installation?

Yes. Wipe both mating surfaces with a clean, dry cloth to remove carbon buildup and old gasket material. Any debris trapped under the gasket will cause leaks. Rough surface prep is the top cause of exhaust leaks on header swaps.

What torque spec should I use when bolting the header down?

Refer to your vehicle's service manual for the correct sequence and torque value. Header bolts are typically torqued in a cross pattern to avoid warping. Over-torquing aluminum gaskets can crush the seal.

Can I reuse this gasket if I remove the header later?

No. Once compressed under bolt load and exposed to exhaust heat, aluminum gaskets lose their sealing integrity. Use a fresh gasket every time you unbolt the header.