The power antenna installed(AC Delco part #22048604) was purchased on ebay and rebuilt by a gentleman in Texas. The antenna was disassembled, cleaned, inspected, lubricated, assembled and tested. He uses a stainless steel wire wrapped in rubber/plastic. He has performed many rebuillds and stated with proper care(lubrication) the antenna should function for a long time.
Pretty sure this is the guy Kirban uses for his rebuilt antennas.