The Stovebolt Site Forums The Shop Area Paint and Body Shop Primer preference?

I would also suggest the epoxy primer but would go a step further and finish the hidden area with a good topcoat. The primer alone is not a waterproof coating and in the very vulnerable metal under the gasket it will absorb moisture if not sealed with a finish coat. I would use an acrylic enamel or acrylic urethane and match the primer to it.