Perfectly normal for a new engine. This is exactly why TTI says not to run their headers on a new engine breaking in. The extra heat a new engine produces during break inperiod can and will damage the paint or coating on headers. Sounds like you found out. Go ahead and run the sucker. By the time you get it all tuned right, it'll be fine.
Straight from the TTI site:
"TTI FOOTNOTE # 17
Warning: First Engine Runs
TTI strongly suggests that you use an old set of headers or set of cast iron manifolds for your first engine run / cam break-in. This will insure that you will not damage the coating and void the warranty of your new headers. Header coating damage usually occurs during the first engine run / break-in when the exhaust temperatures exceed 1200ºF. Excess exhaust temperatures are normally caused by excessively rich or lean air / fuel mixtures and / or incorrect ignition timing."
Here's the link:
http://ttiexhaust.com/Footnotes/17.htm
Don't sweat it. It's perfectly normal.
