Dr. Murdock Head strongly denied yesterday that he was conspiring to bribe two congressmen when he made numnerous cash payments -- some of which were carefully kept free of fingerprints -- to a congressional aide at Head's Airlie Foundation headquarters in the early 1970s.

Head, 57, former executive director of the Warrenton, Va. foundation, took the stand in U.S. District Court in Alexandria to defend himself against a bribery conspiracy charge growing out of the payments. He said the $300-to-$500 sums he gave Stephen B. Elko were intended as campaign contributions to Elko's boss, former representative Daniel J. Flood (D-Pa.).

Head said that when Elko visited Airlie a third time in late 1973 seeking more money, he rejected Elko's overtures because it was not a campaign year. "He began pushing me, talking about 'taxi fare,'" a term Head said Elko coined to refer to the cash payments.

"He kept talking about what Flood and he had done for me," Head said.

Finally, Head said, he went to an Airlie employe, Charlotte Fowler, and said to clean up some money for him to give to Elko. "'Don't I always?'" Head said Fowler replied.

Head said that when he gave the unspecified amount of money to Elko contained in an envelope and wrapped in a magazine, Elko asked: "What's the matter, Doc, are you afraid of fingerprints?"

"Yes, I am," Head said he answered. In answer to a question from U.S. District Judge Oren R. Lewis, Head testified he was concerned by that time about possible blackmail or extortion by Elko.

Elko testified earlier that Head gave him $49,000 from Airlie cash reserves for the purpose of bribing former representatives Flood and Otto Passman (D-La.), key committee chairmen who were in a position to steer federal grants to Head's Airlie Foundation and an allied George Washington University department.

Besides the conspiracy-to-bribe charge, Head, a professor of medicine at GWU and now an unpaid consultant to Airlie, where he still lives, is charged with paying an illegal $1,000 gratuity to Flood, and with conspiring to evade federal tax payments on certain funds allegedly under his control at Airlie and the foundation's film-making affiliate, Raven's Hollow.

Lewis hinted yesterday that at least some tax aspects of the charges against Head might be dismissed. After lengthy wrangling between defense attorneys and federal prosecutor Theodore S. Greenberg over the truth and accuracy of defense charts that ostensibly showed how and where Head had spent Airlie funds during travel overseas, Greenberg made a motion that the charts be stricken from the jury's consideration.

"The jury can decide about that [the charts' veracity]," Lewis said, rejecting the motion. "It's moot now anyway for different reasons." Lewis said no more, but he had said earlier in the trial he would consider a defense motion that the tax counts be dismissed.

All day long Lewis, 79, a gruff-sharp-tongued jurist, interrupted the trial with impatient demands that testimony and particularly attorneys' lines of questioning be refocused and speeded.

Head's current trial is his second on charges that he attempted illegally to influence Flood, Passman and Elko. An earlier tax-conspiracy conviction on Oct. 12, 1979, was overturned by a federal appeals court on Feb. 9 of this year on grounds that Judge Lewis improperly instructed the jury.

Head's defense began yesterday with testimony from former Justice Department attorney John Dowd and former assistant U.S. attorney David Hinden, to whom Elko first made his allegations in 1977 involving Head's alleged bribery attempts.

Dowd testified that he had catalogued Elko's charges and telephoned them to Hinden. Hinden then testified he had incorporated the allegations into an affidavit that later formed the basis for the prosecution of Head. But Lewis refused to allow the affidavit into trial testimony.

Defense lawyer Mark Cummings said later outside the courtroom that the defense had hoped to show inconsistencies between the amount of cash Elko told Dowd and Hinden that Head kept at Airlie, and what Elko testified to alter at Head's current trial.

But with Lewis' refusal to enter the affidavit into testimony, the appearance by Hinden, now a Beverly Hills lawyer, was kept to less than five minutes.

"You brought him all the way here from California for that?" Lewis asked the defense incredulously. "My, my, my."