In addition to the insulating ideas, you may consider ways to vent more heat. The photo below is from ERA's website and shows screened vents in the wheel wells.
I also have aluminum panels around my headers that force more of the heat toward these vents.
Another idea is to not make your hood weather stripping continuous so a bit more heat can escape. If any of this is interesting to you I can get some photos.
Good luck with your build.
Kevin