VHT makes engine enamel aswell. These are the paints I used for my engine:

 

I just had a look at what i got, I have White Knight Engine enamel. But i dont know if it's the one i used on my rail.

I know how to prep for paint ect. painted many things. It's just this damn fuel rail. I'll try scuffing it up. i understand how that works.

 

I had mine on the na powder coated years ago, you can see it here in the photo, the mounts at least though the main part is covered by the plastic cover. It's held up really well, still looks like it's just been done. I'm not convinced paint would have been as resilient.

 

That looks really good. I might just get a bag of parts that i want black and get them powder coated