Thanks for the referral David, but I'm not doing high temp ceramic header and manifold coatings anymore. I fired my high temp supplier last September and am still looking around for a suitable replacement (so far no one is blowin my skirt up though).
In the meantime, I'm referring header/manifold coatings customers to my pal Jason who owns AutoCycle Powder Coating in Chattanooga. His website is autocyclepc.com and his phone number is 423-876-8132. He does nice work, has quite a few good high temp colors to choose from and will treat you right. Be sure to tell him I referred ya.
VHT, follow the instructions and heat and cool, Hang them up, get a big propane torch used for killing weeds an a cheap Harbor Freight infrared heat sensor. Then paint, heat to correct temp, cool, heat again, etc.