I love that paint job. I wonder if a high temp, zinc-rich paint would work well on the steel. It would provide nearly 100% exterior corrosion protection, would maintain turbulence across the fins, and would be very conductive of heat. I think I'll run some tests while waiting to start the build.
Also, we NEED to find a temperature indicating paint, maybe one that remains colored for a period, to show us the hot spots. That would be cool, or hot, as the case may be.
My mechanic and I painted our O-300 "Nu-Cast Aluminum" SP995 from VHT and was very pleased with how it came out. It also went on really thin so you can still see casting details as if no paint was there. I wasn't excited about a thick paint coating that took away from the ability to inspect the surface. I used their SP148 primer, and the finish has proven very durable to chips and all fluids. The color is nice and bright which lets you see really well even in the dark nooks and crannys.