In appointing federal appeals court Judge Antonin Scalia to fill the vacancy created by the resignation of Chief Justice Warren E. Burger, President Reagan is attempting to replace one conservative jurist with another. But many legal scholars said yesterday that the confirmation of Scalia -- while not likely to transform the court overnight -- could eventually leave the court a more conservative institution.

Legal experts said Scalia tends to be more conservative than Burger on some of the court's most hotly contested issues, including abortion, affirmative action and First Amendment rights -- a philosophical difference that will be buttressed by what liberal and conservative lawyers describe as a persuasive manner and impressive intellect.

"In some ways one of the most significant things in the close 5-to-4 or 6-to-3 votes is that the combination of Scalia's affability and brains may swing votes that Burger's aloofness and intellect did not," said American University law professor Herman Schwartz, editor of a forthcoming book on the Burger court.

Scalia, said Harvard Law School professor Laurence Tribe, is "in general much closer to the pure philosophy that Justice William H. Rehnquist exemplifies on issues like affirmative action and the reach of the First Amendment and the incorporation of the Bill of Rights than to the somewhat more centrist views of Chief Justice Burger."

Geoffrey R. Stone, who teaches constitutional law at the University of Chicago, where Scalia taught before being appointed to the U.S. Circuit Court of Appeals here, said Scalia is not only opposed to abortion, but thinks the Roe v. Wade decision -- which Burger joined in legalizing abortion -- "is not justified by the Constitution."

Although Scalia has not handled an abortion case during his four years on the circuit court, he joined an opinion by Judge Robert H. Bork, in a case upholding the Navy's right to dismiss homosexuals, that criticized a related line of Supreme Court decisions finding a constitutional right of privacy.

"The chief justice was more prepared than Judge Scalia is to infer rights from the overall history and structure of the Constitution," Tribe said. "There has been a willingness to go beyond the text in order to preserve the spirit."

Scalia could join Justices Rehnquist and Byron R. White in voting to overturn Roe. Justice Sandra Day O'Connor -- who has criticized the reasoning in Roe but not stated her ultimate position on abortion -- might go along, but that would leave abortion rights intact with possibly a 5-to-4 majority.

Scalia has harshly criticized affirmative action, one of the issues that has splintered the court and on which Burger has taken a generally centrist position. In 1980, Burger wrote the majority opinion upholding a law setting aside 10 percent of federal public works contracts for companies controlled by members of minority groups, although he has dissented from other cases upholding affirmative action programs.

While Burger has written or joined some important opinions upholding press rights, including a 1980 ruling that the news media and public have a constitutional right to attend criminal trials, Scalia has come out against the press in a number of cases on the circuit court.

For example, Scalia broke from Bork, his conservative colleague, in dissenting from a 1984 case ruling that a Marxist professor seeking a job at the University of Maryland could not sue syndicated columnists Rowland Evans and Robert Novak for disparaging comments.

" P erhaps those are right . . . who view high libel judgments as no more than an accurate reflection of the vastly expanded damage that can be caused by media that are capable of holding individuals up to public obloquy from coast to coast and that reap financial rewards commensurate with that power," Scalia wrote. Scholars also said Scalia may take an even more expansive view than Burger of executive branch power. Scalia wrote the unsigned three-judge panel opinion striking down the Gramm-Rudman-Hollings budget-balancing law because the comptroller general, responsible for implementing its automatic trigger provisions, is not under executive branch control. His opinion expressed doubt about the constitutionality of a host of independent U.S. regulatory agencies.