which orange block paint??

Not to hi-jack this thread, but I too, have a paint question!

I have a set of magnum heads that I picked up cheap from a guy that had already gotten rid of his Duster.

The heads had been already rebuilt, and painted gloss black. They were never installed on an engine since the rebuild... so they are not greasy, oily or anything.

What sort of prep do I need to do so I can re-paint them orange?

Thanks in advance!