A simple fix may be to not only insulate the foot boxes themselves with Dynamat, but also to use an exhaust wrapping.
Check out lava wrap, or the foils in the link below, one of many brands.
Heatshield Products
PS: This anecdotally may reduce the life of your headers (but your only talking by a year or so, so you'll get 10yrs instead of 11yrs?), and the trade off is a cooler engine bay, and thus free power & increased efficiency as there's more O2 to burn in the intake
