Looks like the center caps will work with minor modifications to the back retainer/insert.

http://www.cuda-challenger.com/cc/index.php?topic=99165.0

Regarding lug nuts: What would be the proper lug nuts to use with these AR500 wheels? I assume something with a shank, but how long of a shank? I'm fairly certain that the standard acorn style (with the tapered end) that are used with the steel Magnum 500 wheels would NOT be appropriate for the AR500 Aluminum wheels. Is that correct? Thanks again.