I have done business with Millenium before (read: I didn't call them about this) and have generally been unhappy with their attention to detail. That withstanding, the type of nikasil coating on the bores of the cubs can survive very high temperatures (higher than 350C), the problem really is, that the casting itself will relax when you are heating the casting up to powercoat it after plating, thus giving you an untrue bore that that you cannot re-true with out boringthe casting and replating it. :geek: