Hot engine - no start

[g356gear]

On hot days when my bigblock gets up to temp, it does not start. It's not all the time, just occasionally. When it does it, I don't even get a click out of the starter. If I wait 15 minutes, it starts right up. Is this a case of a starter issue or just excessive heat from the headers on the starter that could be answered with an insulator wrap on the starter? Thanks for any feedback.