The Pentagon has finally given the "go-ahead" to actor and Carmel, Calif., Mayor Clint Eastwood for his new movie, "Heartbreak Ridge." After a yearlong battle, Eastwood made the changes that would enable him to use the props he thought necessary from the Defense Department. The Pentagon had said it would not help him based on a reading of the original script on the grounds that it had "excessive brutality by a noncommissioned officer towards trainees and does not reflect the training environment dictated by departmental policy." The Pentagon also said it inaccurately portrayed the Grenada invasion, adding that the film couldn't show a marine making a call to stateside headquarters with a telephone credit card. Humor aside, a soldier did in fact make a credit card call from Grenada to the United States during the invasion to coordinate a portion of the operation.

Writers' Protest

Writers in New York, Paris and Chicago gathered in front of Soviet missions Friday to protest the imprisonment of Russian poet Irina Ratushinskaya. The PEN American Center, organizer of the New York protest, is calling for the poet's release because of serious health complications, involving a kidney ailment, inflamed ovaries, heart problems and "alarmingly high blood pressure . . . " She has been in prison since 1983 on grounds of "manufacturing and disseminating" her poetry.

"No, I'm not afraid," read activist writer Grace Paley from a Ratushinskaya poem. "After a year of breathing these prison nights I will survive into the sadness . . . " Phil Balla of PEN said many of the poems read aloud were smuggled out of the Soviet Union since the poet's imprisonment. Other readers included actress Lee Grant and writers Carol Ascher, Joseph Brodsky, Frances Fitzgerald and Alfa-Betty Olsen. A declaration calling for the poet's release on health grounds was also distributed outside the New York mission. It was signed by Edward Albee, Russell Baker, E.L. Doctorow, Nora Ephron, Allen Ginsberg, John Irving, Norman Mailer, Joyce Carol Oates, Judith Rossner, Gay Talese, Kurt Vonnegut and others.

End Notes

Queen Elizabeth II made her only public appearance of her current American trip yesterday in Versailles, Ky., at the morning prayer services of the 101-year-old St. John's Episcopal Church. She was accompanied by her hosts, William and Sarah Farish, and greeted by the Rev. J. Carl Belden and the bishop of the archdiocese of Lexington, Don Adger Wimberly. "She followed the service very well," said junior warden Virginia Wiglesworth, who sat near the queen. "She stood, she sat, she knelt, she joined in." She was scheduled to visit three other farms yesterday afternoon and will depart for home this morning . . .

The Oregon Episcopal School has had offers ranging from $100,000 to $600,000 from film producers and tabloid publishers to exploit the tragedy of nine people who froze to death on Mount Hood earlier this month. "We've had -- to date -- five offers, some of them near threatening," said Mariann Koop, public relations director for the school. "We've firmly rejected all of them . . . It's repulsive." The two students rescued from the frozen slopes remain hospitalized . . .

Not only can he act but Tom Selleck can compete with the major leagues. Selleck, who dons a Tigers cap on "Magnum, P.I." put on the entire professional get-up yesterday in Detroit and warmed up with the Tigers before their game with the Oakland A's. Up to bat, he surprised fans by blasting two balls into right field seats. "I'm 41 and I can still reach the seats," Selleck said. "But I'm weakening fast . . . "

According to the current Newsweek magazine, a study conducted by two Yale sociologists and a Harvard economist is responsible for "setting off a profound crisis of confidence among America's growing ranks of single women." The study, titled "Marriage Patterns in the United States," found that white, college-educated women born in the 1950s who are single by 30 have only a 20 percent chance of marrying. By the age of 35, the odds drop to 5 percent. The magazine quoted several young woman who felt pressured into marrying since the study was made public last February.