Have not used on headers, but have used on cast iron manifolds with success.
https://www.walmart.com/ip/Black-Ru...e-Enamel-Flat-Spray-Paint-12-Oz/17203457
Unlikely you can do this curing in an oven with larger headers, but I did the 3 step curing in an oven. Has held up well.
Says flat black, but almost has a dark cast iron appearance.

I have Jet Hot coated manifold and sadly they rusted after a few seasons, so tried this on my next build.

Last edited by njmopar; 09/07/21 01:45 PM.