Does anyone know where I can get the black plastic center caps, but without the gel coat emblem already installed? I need four of the center caps for a custom cap I need for the '82. Thanks for suggestions. I've been looking for the blank caps and all I'm finding are the 15" Z28 black caps with no emblem, the 16" caps with the emblem already installed, chrome caps or bare aluminum caps.

 

Best bet is probably finding used caps that the emblems have fallen off. I think I've got at least two of them somewhere, because replacement emblems came with the cap/base.
Next bet would be to buy the cheapest repros, pop the emblems off and sell em. Or keep them for the inevitable day you lose one off your Iroc.

 

The problem with the used center caps is the plastic is so brittle. I might have to just buy new IROC-Z ones and do as you suggested.

 

I was able to find two used caps without an emblem in my stash. One is in nice shape, the other is missing two tabs and a few others are partially broken. Not sure they're worth messing with, but if you came up with 2 or 3 more... The stock caps have part numbers molded on the back side, I haven't looked into it much, just enough to see that it probably pertains to the entire cap with emblem.

 

If you know someone with a 3D printer, or if you want to contact one of the Etsy sellers who will 3D print for a fee, you could have some of these tweaked to accept a center cap and printed:

https://www.thingiverse.com/thing:1235198