I can't emphasize this portion of his advice enough! The key word is "lightly"

Clean the threads with a tap. Go gently. Those are alloy heads and it is easy to mess the threads up. If the bolts look "iffy", replace them. Use a torque wrench when you re-install the manifold.

Use Never-seez or its ilk when you re-assemble.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now