tti's turned gray?

The temp probably got too hot due to running lean. Like Joe said they are picky about that. Break in is especiallly hard on them I've noticed. I didn't have coated headers but painted ones and when I broke in my engine it burned all the paint right off of them. Later that year I blew the engine and rebuilt it and by that time I allready had the carb. dialed in and set the timing right on and that break in it didn't even begin to burn the paint.