I know the '83 and earlier and '84 and later use different bumper fillers, and that they are different around the grille area. Will an '84 grille AND '84 bumper filler fit on an '83, or do I have to change the whole header panel?
bumper interchanges, but the header and grille are totally different. The 81-83 has two different angles where the 84-87 just sweeps straight back. swapping header panels is not very difficult, some slight trimming, but don't remember exactly what.
The big difference is on the 83, is the lower grille extensions are molded onto the fillers. I just sold the last 81-83 header panel I had. I'm thinking you might be able to crossbreed those parts. Its going to look funky. Do you need fillers for an 83? I might be able to come up with a link to a supplier. Let me know. I have one guy in my area(one of those "box" retards) that took the upper and two side chrome moldings off the 83 and filled the holes shut. It looks different is all I have to say.