RETAILING MEGA-MERGER : Questrom Loves a Challenge : Executives: Man behind the Federated deal for Broadway Stores is no stranger to Southland: He once ran Bullock’s chain.

Allen I. Questrom, who made his mark as a top retailing executive a decade ago while running the Los Angeles-based Bullock’s chain, is making another bold impression in California: He’s thinning out his competition.

Questrom is now chairman and chief executive of Federated Department Stores Inc., the giant department store holding company headquartered in Cincinnati that agreed Monday to buy ailing Broadway Stores Inc., an 83-store chain based in Los Angeles.

If the deal goes through, the Broadway name will disappear, as Questrom plans to close some Broadway outlets and convert the others to either Macy’s, Bullock’s or Bloomingdale’s--stores that already are part of the Federated family.

In recent years, Questrom, 55, has been a key player in the Darwinian struggle among the nation’s oldest and largest department stores to survive against the growing strength of specialty retailers and low-cost retailing giants such as Wal-Mart Stores Inc.

He’s also gaining a reputation for buying stores that are on their last legs financially. Broadway has suffered mightily in recent months, and last year Questrom engineered Federated’s $4-billion purchase of R.H. Macy & Co., when Macy was in bankruptcy proceedings.

Questrom was named chairman of Federated in February, 1990. His election was a triumphant return for the Massachusetts native who had spent 23 years at Federated--only to quit in May, 1988, after Campeau Corp. bought the company.

After Questrom left, Campeau ran into massive financial problems, and its Federated and Allied department store units were forced to seek bankruptcy protection.

Questrom, who had gone to Dallas to become chief executive of the Neiman-Marcus retail chain, was hired back by Campeau to run its bankrupt store divisions, influenced in part by a compensation package totaling $12 million over five years.

Then in February, 1992, the Federated and Allied chains emerged from their bankruptcy proceedings and merged to become the entity known today as Federated Department Stores.

Questrom first joined the old Federated in 1965 as an executive trainee with its Abraham & Straus division.

He joined Bullock’s in 1973 as vice president and general merchandise manager. He was named chief executive of Bullock’s in 1984. (Federated sold Bullock’s to Macy in 1988 at the time of the Campeau takeover, only to get Bullock’s back last year with its purchase of Macy.)