Wilbur D. Preston Jr., a senior partner in a prestigious Baltimore law firm and a former president of the Maryland Bar Association, is the leading candidate to become the special counsel charged with investigating the causes of Maryland's savings and loan crisis, according to sources.

The appointment of Preston, a partner in the Baltimore firm of Whiteford, Taylor, Preston, Trimble and Johnston, was described by one source as "98 percent certain" and awaits only final confirmation that neither he nor his firm has any potential conflict of interest in the savings and loan investigation.

Gov. Harry Hughes has until today to name the special counsel, according to legislation creating the post that was enacted by the General Assembly on May 28. However, Hughes' press spokesman Lou Panos said yesterday the governor is unlikely to meet that deadline. Panos also said that Preston was just one of several candidates.

The General Assembly in a special session last month authorized creation of the special counsel post and appropriated $500,000 to fund the probe. The emergency session of the Assembly was called after reports of management changes and allegations of criminal wrongdoing at the Old Court Savings and Loan Association of Baltimore triggered a run on deposits at a number of Maryland's 102 state-chartered and privately insured savings and loans.

As authorized by the legislature, the special counsel's investigation is intended to complement a criminal investigation of Old Court that is being conducted by the Maryland attorney general's office and the U.S. attorney.

The special counsel's investigation, which is to begin by July 1 and be completed by next March, is charged with rooting out the causes of the crisis, including any regulatory or oversight failures by state officials, and finding ways to prevent a recurrence.

Preston, who served as president of the state bar association in 1975, was described yesterday as a veteran trial lawyer and a well-respected figure in the state legal community who has a reputation for integrity and independence. He could not be reached for comment.

"He's a senior statesman of the bar," said Bruce A. Kaufman, chairman of the state's judicial compensation commission. "He's not a man who is prone to quick trigger responses. He's a serious, contemplative individual who is very well suited to that position."

Because of the sensitivity of the special investigation, with its potential for questioning the competence of many state officials and officeholders, Kaufman said Preston would be an ideal choice. "There's no higher quality individual," said Kaufman. "You need someone who is of that ilk to occupy that type of position, someone who is totally disassociated from any of the powers that be."

Fourth Circuit Court Judge John P. Corderman, the outgoing president of the state bar association, characterized Preston yesterday as a "lawyer's lawyer" who enjoys "an excellent reputation for hard work, integrity and for being a very competent professional."

In a related development yesterday, two more Maryland thrifts that were privately insured received conditional approval for federal insurance from the Federal Savings and Loan Insurance Corporation. They are Eastern Savings Association of Timonium and Presidential Savings Association of Bethesda. Another thrift, Madison Square Permanent Building Association of Baltimore, with $54.1 million in assets, received final FSLIC approval on Thursday, bringing to five the number of state associations winning final FSLIC protection. A total of 22 thrifts have won conditional approval.