Painting Engine

I wouldn't use primer if your using paint from the can, just clean all grease off, if your using automotive paint I use a light coat of ppg dp 40 and then single stage enamel, sent a set of heads to the machine shop off my motor once and the guy told me all that shiny paint would be gone after it comes out of the hot tank, when I picked them up he asked me what I used to paint them with because almost all the paint was still there.