U.S. District Judge Oren R. Lewis yesterday rebuked a lawyer for Dr. Murdock Head, former dirctor of the Airlie Foundation, for asking him to grant Head a new trial on charges of engaging in a criminal conspiracy.

"Why in the world should I possibly want to hear it?" the crusty, controversial 78-year-old judge told Head's attorney during a brief court hearing in Alexandria.

As federal prosecutors barely suppressed grins, Lewis chided lawyer Wallace H. Kleindienst for filing the motion for a new trial a month before a federal appeals court is scheduled to consider an appeal of Head's three-year prison sentence. The appeals court won't meet on the case until Nov. 13 and Lewis made clear yesterday he has no intention of upstaging the higher court.

"I wouldn't be so presumptuous as to tell the court of appeals I'd do something if they'd do something," said Lewis.

Kleindienst, who was interrupted freqently by the judge, had argued that Lewis, who presided at Head's 1979 trial, should indicate to the court that he was willing to grant Head a new trial based on affidavits filed by a former Internal Revenue Service agent who was a principal figure in the case. But Lewis said he was unmoved by the statements and agreed with prosecutors who disputed their relevance.

The affidavits are "self-serving, susect and highly impeachable" because the agent "admitted to the FBI to a close personal relationship with Head, the self-anointed major domo of the entire Airlie complex," the prosecutors said in papers opposing the Head motion.

Head, 56, who holds doctorates in medicine, dentistry, and law, was initially charged with conspiring to bribe former Reps. Daniel J. Flood (D-Pa.) and Otto E. Pasman (D-La.) in return for obtaining federal grants for the foundation's enterprises. But The Washington Post later reported that the jury interpreted the conspiracy charge narrowly and did not believe Head guility of conspiring to bribe either congressman. The jurors found that Head had conspired to arrange the improper loan to the IRS agent.

Yesterday's hearing came two days after a Viriginia state judge sitting in Warrenton named a special prosecutor to replace Fauquier County prosecutor Charles Foley and his assistant Roger Inger at the upcoming embezzlement trial of a former Airlie financial officer. Federal prosecutors had sought to force removal of Foley and Inger on grounds that they were involved in a conflict of interest.

The lawyers have been representing other Airlie employes who were being questioned in a continuing federal investigation of the foundation and the financial officer they had indicted testified against Head during his Alexandria trial last year.

Foley and Inger said yesterday they requested appointment of the special prosecutors but repeated their earlier denials that a conflict of exists. Under Virginia law some prosecutors are permitted to retain a private law practice and work as part-time prosecutors.