Black paint or powder coat does not "generate" heat. That is just plain R-O-N-G!

Black absorbs radiant heat and emits heat better than other colors but not by as great a margin as people think.

The thermal conductivity of aluminum is greater than paint or epoxy coatings. So, if one adds a layer of paint the heat will not travel through the combined thickness as well. There is from time to time an argument of whether to paint radiators and the real answer is most radiators are sized large enough that taking away a couple of percent of their capacity by painting does not materially affect the radiator's capacity.

Ideally, one would put a thermal barrier INSIDE the intake manifold runner to slow the heat transfer from either the underhood temps, or the higher temps of the engine conducted from cylinder heads into the intake. This would tend to maximize power. Keeping the heat in the manifold may maximize fuel efficiency.

R.