Dr. Murdoch Head will not have to face trial on a charge that he bribed Rep. Daniel J. Flood (D-Pa.) until Flood's own bribery trial is completed, a federal judge in Alexandria ruled yesterday.

But U.S. District Judge Oren R. Lewis refused to dismiss or set for separate trials 12 other counts of tax evasion, bribery and conspiracy contained in an indictment against Head, 55, director of the tax-exempt Airlie Foundation in Warrenton, Va.

Head, who has pleaded innocent to the charges, faces trial Sept. 10 on the 12 counts.

Head is accused of paying Flood a $1,000 bribe in August 1974 in order to gain lucrative federal contracts for the foundation.

An earlier trial of Flood for allegedly accepting the bribe ended in a mistrial, but Flood is scheduled to face the same charge again in October.

In delaying Head's trial yesterday, Lewis cited the famous Teapot Dome Scandal of 1923 in which former Secretary of the Interior Albert Fall was convicted of accepting a $300,000 bribe from oil magnate Harry Sinclair. Sinclair was acquitted in a separate trial of giving the bribe.

Lewis noted that he was not dismissing the charge. "If I have anything to do with it," Lewis said, the charge will be heard following Flood's trial this fall.

In addition to the Flood allegation, Head, who also chair a department at George Washington University, is accused of conspiring to bribe former Rep. Otto E. Passman and Flood aide Stephen Elko. He was also indicted July 12 on charges of tax evasion and filing a false income tax return, as well as paying illegal gratuities to a former IRS agent.

Lewis yesterday ordered prosecutors to show by next Wednesday why he should not dismiss five counts of the indictment that allege Head paid an $11,000 gratuity to Jesse R. Hare, the IRS agent who approved the Airlie Foundation's tax-exempt status.

Lewis several months ago dismissed an indictment against Hare, stating that the statute of limitations had expired. Prosecutors have appealed the dismissal to the 4th U.S. Circuit Court of Appeals, in Richmond.

Lewis also questioned assistant U.S. Attorneys Joseph Fisher and Theodore Greenberg about the massive conspiracy charge in the 13-count indictment, which prosecutors have repeatedly said is the heart of their case.

"I have doubts that (you) can sustain the conspiracy charge," Lewis said, in part because prosecutors have named as unindicted co-conspirators the Airlie Foundation and a branch of it known as Raven's Hollow, a profit making film company.

"How can you conspire with an inanimate object?" Lewis asked, referring to the complaints.

Fisher said such conspiracies were recognized by case law, and said he would submit brief's on the subject to Lewis by Monday evening.