What 70Sportsroof said. I used them on my 351w manifolds (swapped those for some shorty headers). After I painted them and let them dry to the touch, I bolted them up and drove around to let the heat bake the paint on. I believe that Eastwood mentions that in the directions somewhere. Anyway, I had those on for 2 years and I never say any rust on the manifolds.
"When the chips are down, the buffalo is empty"
Brett C. MCA#51647-'68 FB w/289, T-5, Dark Highland Green, 3.40 8"