In his 1976 book "The Chevrolet Racing engine", Bill Jenkins had this comment: "The last procedure (after bead blasting the dome- my addition) is an application of Sperex VHT white paint to the dome surface followed by a 8-10 hour heat bake with infrared lamps. This is, more or less, a shield to provide faster heat buildup when the car is leaving the line. On the dynamometer we haven't found any power increase from this technique after the heat has stabilized. We know that an engine which as been assembled with bright , shiny, new combustion chambers requires a different "tune up" setting until the chambers have become coated with a fine carbon layer. The VHT paint acts similar to a thin carbon layer and helps promote carbon build up. Without using the paint it takes 6-10 hard passes before we can get back to our race tune-up. By using the paint we can go straight from the shop to the strip with a brand new motor, fire the engine, and hit the first pass with our race tune-up. The carbon buildup , incidentally, is very important in a drag engine. It acts as a head dam or absorption layer inside the chamber and on the head of the piston. During operation it reaches glowing-hot temperatures and assists heat buildup in the chambers during initial full throttle application- quickening response in the first few , ultra-critical feet of the race. "
There is some more but the above covers the topic here.