Just take a 4 1/2" grinder and cut the metal under the plastic. Then take a soldering gun (with flat blade) and melt the plastic to fit the rectangular shape of the newer stereos. It took me about an hour to do this....

SgtDel
aka "Andy"
www.delbridge.net
1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4