i probally send atleast 1 set of headers a week to be coated, there are many different coatings. most on them are a aluminum base coating. on normal stuff (non turbo stuff) this coating is ok. it will work with temps up to 1300f at which the aluminum starts to melt, or peal.. this is avalible in silver (flat or high luster) black, and flat colors. most of the time the headers are coated in and out. this helps with heat and exhaust scaviging. over 1300f you need a coating that only JETHOT uses. only comes in flat black, and is very costly. normal v-8 headers are $205.00 coated in & out. in the extreme coating in & out the cost is $825.00..
as far as helping with overheating the will to a point. on our drag car we can idel into the staging lanes, then into the burn out box, do major JOHN FORCE style burn out, back up, pre stage, open the nitrous bottles, turn on the data logger, wait for other racer to do the same, finally stage, make a 6.70 @ 212 mph pass, shut off, and pull back to trailer. at this point pull the hood, front end, and grab the headers with out being burnt, pull plugs and so on.
the under hood temps are lower. now as far as helping with overheating the coating can help by not letting exhaust heat to be soaked into other items like the head, hoses,radiator, and so on. plus the coating helps with rust, and apperance.
scot