I purchased this:

http://www.carid.com/1985-chevy-cama...e-3147528.html

I took it to my body guy and asked him to install it after painting the car. Before, I had removed the factory grill (the built-in Camaro plate) because someone had drilled multiple holes in it. Knowing I was going with this billet one, I didn't bother keeping the factory one.

My body shop called today and told me that the hardware I dropped off with the grille wasn't enough; there was nothing to stop the grille from moving side to side. They weren't sure if something was missing, or if this grill was supposed to be installed over the factory one (I don't think this is the case, but I'm not positive). Looking for any installation advice that might help. Thanks.

 

Chevy Camaro Z28 1982-1987, Polished Aluminum Billet Grille by APG®. Bolts over original grille. Enhance exterior and add stylish accent to your vehicle with Billet Grille by APG. The Grille is made of aluminum for high durability. The Billet Grille is designed application-specific to fit your vehicle perfectly.

thats copied and pasted from the website you linked (with the important part highlighted)

im sure your if your body man is competent enough he can fab up some mounts to use without the original grille.

 

oops

 

I have one for sale 25.00 plus shipping