Two top contenders for secretary of education each spent an hour this week presenting their credentials to a group of conservatives who have called for important shifts in education policy in President Reagan's second term, it was learned yesterday.

The appearances were with the knowledge of the White House, which is searching for a successor for T.H. Bell, who has resigned effective Dec. 31. Bell was a particular target of conservatives during his tenure.

William J. Bennett, chairman of the National Endowment for the Humanities, and John Silber, president of Boston University, made their presentations at the offices of the Committee for the Survival of a Free Congress, an umbrella organization of about a dozen conservative lobbying groups.

The White House supplied the names of leading candidates. "We knew that there were certain conservatives who wanted to meet with the candidates," Becky Norton Dunlop, deputy assistant to the president for presidential personnel, said. "We told the candidates there would be no problem if they did."

"We did not discourage the candidates from meeting with them," she said.

Ronald P. Preston, a Senate Labor and Human Resources Committee staff member who attended the "ad hoc, off-the-record meeting," said yesterday that the White House contacted Ronald Docksai, the committee's staff director, last week and indicated that the administration wanted to make a "reasonably quick" decision on a replacement for Bell.

Education issues are routed through a subcommittee.

"Our sense is that this time they're going for a conservative educator , or an ex-governor, a no-never-mind person," Preston said. "Someone actually more in keeping with the thinking of this administration."

According to Preston, the White House identified Bennett and Silber in response to the request for a list of the leading candidates, and the conservative committee then extended an invitation for them to appear at its Northeast Washington headquarters off Capitol Hill.

Bennett and Silber were questioned about their views of the federal role in education during the meeting, according to Preston.

Conservatives are particularly interested in the subjects of increasing local control of schools, merit pay, improving school quality, discipline, tuition tax credits, education vouchers and school prayer.

Paul Weyrich, president of the Committee for the Survival of a Free Congress, was represented at the meeting by Connaught (Connie) Marshner, a committee director who organized the meeting, according to Dunlop.

An arm of the panel, The Free Congress Research & Education Foundation, recently published "A Blueprint for Education Reform," a 300-page book with the lead article, "Overview of Education Reform Issues," by President Reagan.

"Since our administration put education at the top of the American agenda," he wrote, "we've seen a grassroots revolution that promises to strengthen every school in the country, based not on more federal spending and interference, but on state and local reform."

Donald J. Devine, director of the Office of Personnel Management, who has been considered a top candidate, did not attend. His office said he has been in Florida all week. Preston said Devine is no longer considered a "serious candidate."

"It's no secret," he said, "that most of the conservatives in the city seem to like Bill Bennett." Conservatives, he said, are "very apprehensive" about a liberal choice.