Hot spots on the intake manifold on a 454 Crusader

I noticed a hot spot on both of my intake manifolds on my 1990 Crusader 454's. I recently repainted the engines and now find these hot spots/ burn marks appearing. They are located on the left side of each manifold close to the rocker covers adjacent to the quadrajet carbs and are appr 3" in circumference. Any ideas what may be creating these? or is this typical? Both engines are operating normal with the oil pressure good and no leak or burn of oil. Each engine has 1500 hrs and I believe them to be original engines with no major work done.

Thanks in advance

That is your exhaust crossover area; it heats the carb to intake valve runners, aiding in atomization of the fuel. Normal to burn regular paint there, and it will stink for a while.