IIRC, 1st gen wheels have around +35mm offset while 2nd gen wheels have around +52mm. So, a 2nd gen wheel on a 1st gen will sit farther inboard. I can't say for sure if it would hit anything, but I think I remember one or two people here that have used spacers to mount up 2nd gen wheels (z34_nut is one)
Here's an old post (with z34_nut's picture): http://www.w-body.com/forum/viewtopic.php?t=23172