Physics doesn't discriminate based on color or brand! The fact is engines are usually painted for rust protection regardless of color. As was said earlier, black is impossible to detect oil leaks, I built a Ford 7.3 L for a guy not long ago and he wanted to paint it Ford Oval Blue, I said that would look ugly as sin in his burnt orange truck and said it would be better to paint it black, I had already done it in black and he brought up the oil trace issue. We both agreed it would look much better painted Cat Yellow so I went to the local Cat Dealer and purchased the correct paint, he and I agreed it did look cooler in yellow. Those old 7.3l did look a bit like the old 11xx and 32xx series Cat V8 if you didn't look long at them. As for the black engines, engine masters did a show that was published in some mags some time back. Results as far as I can remember were somewhat insignificant on account of the engines temps depending more on the thermostats, and the cooling system as a whole. For what little difference it really makes is this, iron heads have been found to actually make more power but run hotter which is an issue in itself due to combustion control. Engines running aluminum heads seem to tolerate slightly more ignition advance because they keep the charge and combustion temps cooler, aluminum as well all know absords heat better and since the fluid system is tasked with removing that heat, aluminum also releases it faster and better than iron. It is know that iron blocks are more stable and stability is a key factor in engine function so painting the iron block tends to keep block temps a bit higher internally, this is a slight benefit to helping the pistons and rings to fit and seal a tiny bit better. Then to either use real aluminum heads or paint the heads aluminum. Since the heat in an engine is dissipated from the surface either inside or outside and you would have a pretty hard time coating the inside of the cooling areas unless you dipped the parts in paint, color of any engine block becomes more an issue of preference. Black guns look cool or scary based on the persons attitude towards them just the same as engines. The difference is only measured on a dyno and is very miniscule.
