My 69Z had headers on it when I purchased. During the restoration, I look a long time for a set of originals but they all were pitted and looked bad, relative to everything else that looked new after the restoration.
I purchased a set of GM Restoration Parts brand repros from Rick 1st Gen. They fit and look great. They need to be cleaned thoroughly several times with lacquer thinner then with soap and water and allowed to dry out for several days (or bake the moisture out of them at 200 degree for a period). Then paint them with high temp paint, and baked according the manufacturers recommendations.
I used Seymourís "Pit Crew High Temp 1200 F "Cast Blast color, #16-2668. Eastwood also sell a similar nice product called Factory Gray High Temp Coating #10395Z, $15.99 per 12 oz spray can. I donít recall where I got the Seymourís product.
The pictures of my manifolds show the color which appears very natural. My manifolds were painted back in 2000 and still look great...no rust!