Heat in the footbox is a real issue, and always has been. In a street Cobra, the exhaust is directly under the floorboards. In the S/C configuration, the header tubes are directly in front of the foot box. Of course some heat will end up in the foot box. Everyone who drives a Cobra knows this.
Fortunately, there are a number of simple ways to mitigate that fact. As said, shoes would be the first step.
But there are lots of other options if you like to drive without shoes.