Tires for '95 Z28

I have a 95 z28..when I bought the car they didn't have the stock rim/tire. They came with 245/40R18s..I'm wanting to get the stock rim/tires but I'm not too sure what to look for..seeing how they have the corvette style brakes. I found a used tire/rim, I think it was off a IROC with 245/50R16 tire..we had to saw off the lip on the inside of the rim because it was rubbing on the inner hub and wouldn't set right..It was hard enough finding a rim/tire that would fit my car. I just moved to hawaii..and have been told my wheels are hard to find. Trying to find a full 245/50R16 set with the rim so I can fix the alignment before the tires wear completely, had to replace the one tire because it blew which destroyed the rim :(. Any help would be appreciated!