If you go to the cb750 bit of this forum, and look for UK Petes F2 build....... he used Por 15 and said this "i have opted for POR 15 engine enamel for the engine, as this seems to be the toughest finish, and totally petrol and solvent proof"
But, on his first day of riding it, one of his boots lace eyelets, scratched up that paint, which was unfortunate. So, it appears its not bullet proof.
But if you take a look it may help in deciding if this was the finish you were after.