Members of the two influential black voter groups gave Henry E. Howell their overwhelming endorsement for the Democratic nomination for governor today -- an endorsement some blacks said was essential in his difficult race against Andrew P. Miller.

The two groups, the Virginia Crusade for voters and the Democratic Black Caucus of Virginia also endorsed Richard S. (Major) Reynolds III for the Democratic nomination for lieutenant governor and Mclean lawyer John Schell for the nomination for attorney general.

The endorsements for Howell and Reynolds were not surprising. Howell, a former lieutenant governor, was one of the most outspoken advocates of black rights during the period when legal segregation was being eliminated in Virginia. Reynolds has a long record of support for black rights and black political figures in Richmond.

The crowd of about 200 at the joint endorsement meeting in a Richmond junior high school was dominated by Richmond residents. Nevertheless the endorsements of the Crusade and Caucus have traditionally been influential with black voters in all parts of the state. Some black political figures and campaign officials, however, say they have sensed a growing independence among city and county black voter groups outside of Richmond.

Neither of the two gubernatorial candidates was present. Former Attorney General Miller, was represented by his minorities coordinator, Larry D. Jones.

Jones pointed to Miller's record of opening up the attorney general's office to blacks and said. "Andy Miller will not be a for-whites-only governor."

He contended that only Miller can defeat Republican Lt. Gov. John M. Dalton in the general election and said, "We cannot afford to gamore with our political future. Andy Miller is a winner and when Andy Miller wins, blacks will win."

Jones devoted part of his speech to attacking a Washington Post story about attitudes of the Miller campaign toward the black vote that ran in yesterday's editions. The story quoted Jones as saying that the Miller campaign has "written off" the black vote.

Jones said the story was full of "misrepresentations, error and quotes taken out of context."

He declined in an interview after his speech to single out specific errors.

Howell was represented by three influential black political figures, Richmond Mayor Henry Marsh, Suffolk Vice Mayor Moses Riddick and Democratic National Committeewoman Ruth Harvey Charity of Danville.

They recited Howell's record of support of blacks. Riddick also attacked Miller's efforts as attorney general to remove Virginia from coverage by the federal Voting Rights Act. "If it were not for the Voting Rights Act, we black elected officials would not be here."

The vote to endorse Howell was 157 to 23. An effort to make it unanimous was blocked by a few members led by Bobby B. Stafford, an Arlington lawyer.

Some persons participating in the meeting viewed the Howell endorsement simply as a ratification of wellknown black sentiment around the state. "It doesn't matter what we do here, Henry is going to get 90 per cent of the black vote regardless," Dr. William Ferguson Reid, former member of the House of Delegates in Richmond, said in an interview.

Nevertheless, Howell's campaign is matched against a much-better financed Miller organization and any withdrawal of support that has been important to him in three previous statewide campaigns would have been viewed as a critical loss.

Reynolds was endorsed with 107 votes to 60 for state Del. Ira M. Lechner of Arlington and eight votes for Charles S. (Chuck) Robb of McLean.

Lechner has a long record of black rights advocacy as a lawyer and state delegate. However, he was clearly outmatched in this contest by Reynold's Richmond friends. The endorsement of Schell for attorney general was something of a surprise and the first major break for him in a campaign in which he is matched against three better-known opponents.

Schell on a second count received 62 votes. Del John L. Melnick of Arlington received 50 votes, Del. Erwin S. Solomon of Bath County and Del. Edward E. Lane of Richmond received two votes each.

Schell is an experienced utilities lawyer who has represented the Consumer Congress of the Commonwealth of Virginia in cases in which rates of the Virginia Electric and Power Company were set.