wierdly i looked on another forum for an unrelated matter, and right at the top was a 22 reply thread on this very subject.

in-fact they was all painting turbine housings and manifolds!

VHT flame-proof or Duplicolor 1500 they seem to be using with no problems at all even at that sort of mental heat, as well as some using BBQ paint.
VHT flame-proof seems best.