Engine colors...

Ford Blue oil pan. easier to see any leaks.

Unless your buddy got a prefessional outfit, you wont be able to coat anything that wont fit an oven. You wouldnt want to coat the radiator anyway; they have special heat transferring paint as it is(so I've heard...makes sense to me).

For colors, I have rather specific tastes. I think if you have an all-blue engine, the black pan will look funny. I once considered a gold engine block, but someone told be it would look like a Buick or Pontiac or something and that pretty much killed it. Now the only painted things are my valvecovers, damper, and block.