Instead of paint, I’ve been pleased with manifold dressings that are made for cast iron. More can be applied with an old toothbrush at any time to touch up areas. I think it holds up pretty good.
Here’s a picture of my 230 manifolds. Intake has Calyx manifold dressing. It’s pretty expensive for what you get. I ran out of Calyx so I decided to try Rutland Pot Belly Stove Polish on the exhaust. I like the contrast.
I also used the Rutland stove polish on the LS engine exhaust.