Really dig the project and glad to see another bird! I will send you info on the grille, I know a company in CA that does them, and I believe they are not too pricy and are well made (actually metal not plastic). Steve has a set on his Firebird currently mocked up and in process.
I did something similar on my wife's Firebird, modified front fenders, grafting 69 louvers and shaved the rear louvers.
I dig the color choice, I believe ZVT was planning on a white pearl of sorts, so some inspiration (not mine):
old pic showing the 69 grafting for reference:
BTW where are you located?