Just throwing this out there. I had a '65 Sprt Fury with an RB and black headers. Radiated so much heat from the headers that the edges of the suspension cover would smoke. Solution? Painted the headers white and problem solved.
Makes sense - radiant heat again. The direct exposure of the headers to the suspension cover would heat the cover due to the high temperature differential and the amount of radiant heat dissipated.
Radiant heat is all about a high temperature emitter directly heating a surface within line-of-sight. The amount of heat radiated can be moderated by the color or coating of the emitter or receiver.
