you can try this stuff, a lot of guys use this on the heads, they say it don't burn off where the exhaust ports are, and it only takes 350* to cure, which should not warp the manifold
https://www.kbs-coatings.com/XTC.htmlOr you can use this stuff, no heat to cure, and it comes in Satin or Gloss but it says
(Great for high temperature automotive applications including the use on cylinder heads, engine blocks, brake components and even inlet manifolds, without yellowing up to 250° Fahrenheit.)
I would be afraid of the "without yellowing up to 250* F" I think the intake might get hotter than that in some places
https://www.kbs-coatings.com/DiamondFinish-Clear-Aerosol.htmlI have used their XTC paint on a set of headers with great results, I will be using it on my intake as my intake will be sandblasted so it won't have the factory new finnish, the Aluminum color is pretty close.