here is how I did mine:
https://www.ramforum.com/posts/1260424/
First, I got some of those plastic gloves, not unlike what you see in a doctors office. Skin has oils and those oils will cause paint issues. Fish eyes and the like.
Next, I used a quality paint thinner and a clean linen rag.
Old T-shirts work well.
Then used those, liberally doused with paint thinner, to clean the entire engine cover. Once cleaned, allowed it to dry.
Grabbed a can of plastic adhesive promoter, which can be bought at wal-mart or automotive parts store. (NOTE: Try to stay within the same brand for all your paints. Just makes things a little easier, since they are designed to work together, I do not recommend one, over another.)
Sprayed very light coats, on the well cleaned engine cover, according to directions on the can.
Figured it was far better to lay down the adhesive promoter, LIGHTLY, LIGHTLY, LIGHTLY. And allowing it plenty of time to dry, properly.
I want that STICK, to the engine cover, so my paint can stick, to it.
Once the adhesive promoter was dry. I then did the same with the Primer.
Applying light coats, according to the can itself.
Did more than a few coats of Primer, since I was going to sand this down, to try and smooth out the texture of the engine cover. If you look closely, it has a slightly bumpy surface. I wanted it smooth as a baby's bottom.
After sanding the primer, needed to re-clean the engine cover, as stated above. Then applied final coat of primer.
After that final coat of primer dried, started in on paint.
Now, some guys have gone all out, using lots of colors, some have even done fine artwork. I;m not an Artist and figured two colors was plenty. The color of my truck and good old black, everything matches black.
Masked off & painted the middle section, first.
Once dry, taped it off and painted the sides.
(NOTE: If you are planning on doing two different colors, in your middle section. Say, Gloss black and flat black, this is the time to do second color.)
Once the completed middle section was done and dry, taped it off.
Simply too my time, used good paint tape.
Letters could have been bought, on ebay , as perfect fit stickers but then it is only the top of the letter that has color. I decided to tape off the letters allowing me to get paint on the sides of the letters too.
Once everything was painted, clear coat everything.
I used four coats of paint, followed by four coats of clear.
Just take your time, sand between costs to remove the bumpiness of the material and provide smooth look and feel.
make sure to clean , just prior to painting, with paint thinner and old Tshirt