The Virginia Crusade for Voters, the state's most influential black political group, today endorsed Democrat Gerald L. Baliles' race for governor, a move that some party leaders say should help solidify what they have feared could be lackluster support by blacks for the party's top candidate in the Nov. 5 elections.

The group, after hearing public appeals from the candidates, and after a closed meeting of members that lasted two hours, formally backed Baliles for governor, and his two Democratic running mates, state Sen. L. Douglas Wilder of Richmond for lieutenant governor and state Del. Mary Sue Terry of Patrick County for state attorney general.

Republican gubernatorial nominee Wyatt B. Durrette, and Del W.R. (Buster) O'Brien of Virginia Beach, the party's nominee for attorney general, also addressed the group of about 400 black politicians and civic leaders at a private club in Richmond.

The Virginia Crusade for Voters traditionally has supported Democrats, helping provide the party with support from the state's black voters, who comprise one of the most important elements in the coalition Democrats say they must have in order to win in Virginia.

Durrette said in an interview before the vote today that he did not expect to get the endorsement, but would be happy "with a strong showing." Baliles received 297 votes and Durrette, 91, a showing that some Democrats called "respectable."

William F. Hurd, a Durrette political adviser, praised the results. "Wyatt, if this is an indication, will get 24 percent of the black vote election day," he said.

"Durrette spent a lot of money and a lot of effort but failed miserably," countered Robert L. Watson, executive director of the state Democratic Party.

The Democratic slate endorsement comes at a time when some party leaders have expressed concern that Baliles, a former state attorney general, has not done enough to appeal to blacks, who make up about 15 percent of the state's electorate.

Some have been fearful that the party will assume that black voters will automatically turn out in large numbers for the Democrats this fall because the party ticket includes Wilder, the first black to be nominated for statewide office here by a major party.

"Some of the vibrations I have been picking up, not my own personal feelings . . . is some people feel excluded, left out," said state Del. William R. Robinson (D-Norfolk), who is black. "I know Baliles . I trust him, but surrogates are no substitute for the candidate."

Baliles, standing outside the Flamingo Club awaiting today's vote, said he is not taking black voters for granted. "The campaign is not over, nor is it always visible," he said.

Aides said Baliles has met privately with black leaders and will step up public appearances that will reaffirm his support among blacks.

In recent years, the black vote in Virginia has become a crucial bloc in Democratic campaigns. Democrats point out that Gov. Charles S. Robb led a Democratic sweep in 1981, with 96.4 percent of the nearly 200,000 blacks who cast ballots that year supporting him.

Robb, however, was criticized early in his race for failing to pay more attention to black issues.

Durrette acknowledged that he could not realistically compete for all blacks votes this year. He said he hoped to get between the 8 percent black vote President Reagan got last year and the 21 percent that Republican Sen. John W. Warner then received.

Democrats contend that Durrette is unlikely to get more than 8 percent of the vote, but they acknowledged that Durrette is making a concerted effort to win black votes that could undercut Democratic margins in a close race.

Wilder was clearly the favorite here today. His opponent, Republican state Sen. John H. Chichester of Stafford County, did not attend the meeting. Chichester got only eight votes, even though the Durrette campaign brought in two busloads of supporters from Newport News. A black political group there endorsed Durrette last week.

"It's strange that none of the Republicans mentioned Ronald Reagan even once, when they run around the state mentioning his name all the time . . . . They must think we're fools," said former Richmond mayor Henry Marsh in an interview. Marsh gave a speech for the Democrats during the closed portion of the meeting.

Democrats insist that Durrette will be hurt in the black community because of his backing by some conservative former Democrats, including former governor Mills Godwin of Suffolk.

Godwin, a former segregationist whose remarks are believed to have played a role in the Republicans' 1981 defeat, recently campaigned with Durrette and critized Wilder's efforts in 1970 to remove "Carry Me Back to Ole Virginia" as the state song. The song includes references to "this ol' darky" and "massah" that are offensive to blacks.

"Godwin Does It Again," said a headline in this week's Richmond Afro-American newspaper.