Header hardware prep

Hello

I just pulled the factory manifolds off of a 1974 318 (after soaking the bolts/studs in penetrating oil over the course of a few days), in favor for a set of headers.

How should I prep the new header hardware before I install the headers? Should I anti seize them or apply some kind of rtv (thread sealant). I’m unsure of wether or not the bolts thread into water jackets. Heads are still cast iron if that has any affect on the anti seized used.

Thanks