Engine paint help. Orange Over Black.

[imdarren]

I'll be buying a new GM crate motor soon.
They come painted black, but I want to paint mine Orange.
Should I use Grey primer first then orange?
If I use primer, does it need to be high temp? Do they even make high temp primer? If so, where do you buy it?
I don't think just trying to cover the black with orange will work very well.
It's going to be a new motor, so I dont think a paint strip product would be a good idea.

Your advice would be great!

Darren