[knomadd]

If you're not looking for a glass smooth surface, primer isn't really needed. I've only used primer once on an intake manifold and it didn't make a difference what-so-ever. Save your time and money. And I use the Dupli-color engine enamel too. On a driveable vehicle, I'll take it to a local quarter car wash, spray it with engine degreaser, use a scraper for large particles then wash it off and let it dry. Before I paint it, I'll use brake cleaner for the residue and just paint it.

If you have peeling/chipping paint, you'll want to scrape that off or your new paint will still come off.