GREAT AMERICAN MGMT<GAMI> HAS ATCOR<ATCO> STAKE Great American Management and Investment Inc told the Securities and Exchange Commission it acquired a 7.7 pct stake in Atcor Inc. Great American said it bought the stake for investment. It added that it has also considered--but not yet decided--to buy additional Atcor shares, either in the open market, in private transactions, through a tender offer or otherwise. Great American said it paid about 6.1 mln dlrs for its 462,400 Atcor shares. It said its most recent purchases included 191,400 shares bought March 18-April 6.