That is a great question and a heat deflector is going to be my first course of action. I have ordered some heat shielding and tape to line the box. I also ordered several PC cooling fans to install under the dash to move the air. When the outside air ambient temp is 109, heat is an issue.Sorry for the obvious question, but what heat blanket protection did you use in the footwell? Have you built any kind of heat diversion shield after the radiator to push hot air out the hood slot? Cam T has a good discussion on this. I think Aaron does as well.
I coated my footbox with lizard skin. Heat shroud is on the to do list.