I did the same thing to my valve cover(the plastic piece that is). It was complicated. Did you know that Krylon makes a paint now just for plastics??? Krylon Fusion is what I used. Left the letters black and made the rest red. I have a few other things that I want to do it to but haven't had time. ---Looks good man.

 

is the valve cover plastic or what material is it made of.

 

Looks good!!!
Do the valvecover!

Its a magnesium/aluminum composit cast, not a real high quality part if youre looking to polish it up like I did, I milled off "dodge" and the "ribs" on mine then proceeded to polish the letters but it didnt turn out to the mirror finish like I wanted but its good enough!