By starter wont function, I assume it wont turn at all when warmed up? Yes, it could be getting too hot from the headers. You can try to make a heat shield to deflect the heat, or try the header wrap. I haven't tried the header wrap before but have considered it, if you use the wrap and it does a pretty good job can you report back to us and let us know? Running a larger gauge wire to the starter could help too.