A federal judge yesterday sentenced Airlie Foundation creator Dr. Murdock Head to 4 1/2 years on bribery conspiracy charges, but hinted that he would cut the prison time sharply if Head performs "worthwhile work" on the roots of violence among American youth.

District Judge Oren R. Lewis urged Head, convicted July 1 of conspiring to bribe two powerful Democratic congressmen in exchange for lucrative government contracts for Airlie, to study ways to "stop, slow down this horrible behavior of our juveniles."

Citing statistics that the bulk of violent offenders fall between the agest of 18 and 24, Lewis said: "We don't have the old-fashioned home attention any more, with so many women working. I'd rather see you [Head] spend most of it [the prison term] on the outside."

Head, a George Washington University professor who holds graduate degrees in medicine, law and dentistry, said later he was "very interested" in pursuing Lewis' suggestion.

"The judge and I are in complete agreement," Head said.

Defense lawyer Frank W. Dunham Jr. said Head's conviction will be appealed. But he called Lewis' comments significant and added: "We will take the judge's hint."

Lewis' 10-minute remarks -- during which the 57-year-old Head gripped a courtroom podium tightly -- were the first sign in the government's nearly five-year prosecution of Head that the end to the criminal case might be in sight. Head was convicted on similar charges in October 1979 and sentenced by Lewis to three years in prison, but the verdict was overturned on appeal and a new trial ordered.

Head was accused of paying $49,000 in bribes to former Reps. Daniel Flood (D-Pa.) and Otto Passman (D-La.) through Stephen B. Elko, a Flood aide who testified he visited Airlie frequently in the early 1970s to pick up the cash payments. Head denied under oath at both trials that he attempted illegally to influence the congressmen, who headed House appropriations subcommittees.

Lewis yesterday criticized both sides in the often-bitter trial for dragging out the proceedings and called the expenses incurred "totally and completely unjustified."

Noting that Head has spent about $500,000 defending himself and other employes of Airlie, a Warrenton, Va. conference center, Lewis said: "Of all the defendants I represented for a mere pittance . . . I never saw a half-million. I'd be a rich man today."

Turning to the prosecution table in the courtroom, Lewis added: "The government has wasted a lot of money, too. They've been known to overcook."

Lewis heavily criticized a government memorandum, filed late Thursday, asking that Head be made to pay $18,516 for the partial cost of his own prosecution.

"Since when do I penalize rich people?" Lewis demanded after assistant U.S. Attorney Theodore Greenberg suggested in court that Head had at least $255,000 in a pension fund. "He [Head] married well. He had money, presumably, at one time. I believe in equality. There's nothing wrong with working hard and saving money."

Lewis said the government request was the first such plea he had seen in 21 years as a judge.

Airlie officials have often criticized the government's investigation as vindictive and a vendetta against the tall, graying Head.

"You've got to wonder, when they [the prosecutors] have their entire fraud unit tied up in chasing Dr. Head," said defense lawyer Dunham, himself a former federal prosecutor, after yesterday's hearing. Federal prosecutors declined to comment on the charge.

Besides the latest conspiracy conviction, Head faces a tax case in which the IRS has demanded nearly $3 million in back taxes and penalties, growing out of revelations about Airlie's operations. The agency has said that Airlie's tax-exempt status also is under review.

It was revealed in court yesterday that Airlie's board of directors -- whose members include former Defense Secretary Melvin Laird and GWY president Lloyd Elliott -- has voted substantial funds to help pay Head's legal costs. Head said later the funds amount to "well over $100,000."

He is obligated under Virginia law to repay the money if his conviction is upheld, Head said.

Federal prosecutors also have presented evidence to a grand jury in Alexandria on possible contract fraud involving Airlie's government work. Foundation executive director Frank Kavanaugh said he was served with a subpoena as he left the courthouse yesterday, directing him to appear before the grand jury panel Aug. 10.

Yesterday's sentencing was preceded by a defnese motion asking Lewis to dismiss Head's conviction on a related charge that Head paid an illegal $1,000 gratuity to Flood in August 1974.

Dunham told Lewis the prosecution had failed to present evidence that Flood had performed any official act in return for the payment. But assistant U.S. Attorney Joseph Fisher contended there was "plenty of evidence that the $1,000 related to services rendered."

Lewis agreed. "The charge went to the jury and I'm not going to upset it," he told Dunham, who once served the judge as a law clerk. The motion was denied.

In his statement before sentence was imposed, Dunham stressed that Head's payments to Flood, which Head testified were campaign contributions, all ocurred from 1972 to 1974.

"It was before the Watergate reforms. The way campaign funds are raised [today] has changed," Dunham said. "That's probably good, but it doesn't make Head more guilty or less guilty."

Prosecutor Greenberg countered that Head had "corrupted the appropriations process." Although the illegal payments stopped in 1974, after Head allegedly warned Elko to "lay low" because of the furor over Watergate, Greenberg said, the conspiracy later "went on its merry way."

"Frankly, in my opinion," Lewis told Head, "this has gone on too long for everybody. There is no question in my mind you have committed some wrongs and that the jury had ample evidence" to support its verdict.

He then pronounced a sentence of three years on the bribery conspiracy charge and 18 months on the illegal gratuity allegation. Lewis has 120 days, if the conviction is upheld on appeal, in which to alter the sentence.