A surge of black voters provided crucial victory margins this week for a half-dozen white Democratic candidates across the country, but white voters failed to reciprocate for the candidates who most symbolized black political aspirations.

Outside several polling places in Texas, hundreds of blacks waited in line for hours in a heavy downpour, and three of four voted for Democratic challenger Mark White in his upset of Gov. Bill Clements.

In the economically depressed Midwest, Democratic candidates for governor pulled more than 90 percent of the black vote in what black leaders called an angry protest against Reaganomics.

Blacks also saw their numbers jump in the House of Representatives from 18 to 21, with two newcomers drawing heavy white support. One, Alan Wheat, a liberal Missouri state legislator, easily beat a white Republican in a Kansas City district that is only 23 percent black.

But many blacks reacted bitterly to the unexpected loss of California's Tom Bradley by 52,000-plus votes out of more than 7 million cast in his bid to become the nation's first elected black governor.

Three percent of those who voted for Republican George Deukmejian said in a Field exit poll that they refused to vote for Bradley because he is black. That translates into 150,000 votes, three times the winning margin.

"Of course it's racism," said California Assemblywoman Maxine Walters (D), pointing to Bradley's moderate image and long experience. "If he can't win, do you think there is one better that they will vote for? He was the best of what a fair society could look for and they rejected him. There's a lot of disillusionment out there today. Once again, blacks feel they have been rejected by white America."

Some believed Deukmejian's newspaper ads -- "because we need a governor for all of California" -- had racial undertones strikingly similar to a line used by Republican Webb Franklin -- "a congressman for us" -- in his narrow victory over Robert Clark.

Clark, a moderate state legislator widely accepted by the white establishment, was favored to become Mississippi's first black congressman since 1883.

One reason was offered by Yazoo City housewife Jymme Bond, 41, who said after voting for Clark's Republican opponent: "I can't lie about it -- it's the way I was raised -- but I just don't want to see a black man in that office."

Elsewhere in the South, blacks voted 5 to 1 for former Alabama governor George Wallace, who once blocked them at the schoolhouse door, and were instrumental in dumping four freshman Republicans.

"They wanted to send a message to the White House that Reaganomics is not playing," said Eddie Williams, president of the Joint Center for Political Studies, which specializes in black affairs. "Blacks decided who was coming to the House and who was staying home."

In Chicago, mobile vans at 30 welfare and unemployment offices and hundreds of ads on black radio stations lured 130,000 new black voters onto the rolls. Black turnout in some Chicago wards was nearly 80 percent. An ABC poll showed that 91 percent of blacks statewide voted for underdog Democrat Adlai E. Stevenson III in his surprising showing against Gov. James R. Thompson.

"You had a lot of anger," said Rep. Harold Washington (D-Ill.), who is counting on their support for a possible run for mayor of Chicago. "The Reagan program has devastated most black communities here."

Another underdog Democrat, Pennsylania Rep. Alan E. Ertel, won every black ward in Philadelphia and nearly overtook Gov. Richard L. Thornburgh. Thornburgh, who angered blacks by walking out of an NAACP convention, got less than half the 50 percent of the black vote he polled in 1978.

In New York, Lt. Gov. Mario M. Cuomo (D) won 93 percent of the black vote in a narrow victory over Republican Lewis E. Lehrman. "Blacks went very big for Cuomo and it made part of the difference," said pollster Patrick Caddell.

In Houston, Democrats hit their quotas in some black precincts by mid-morning, and several polling places ran out of ballots as blacks joined Hispanic voters in upsetting Clements.

Black support swelled over previous years for several other Democratic gubernatorial candidates, ABC found. In Ohio, Richard Celeste got 89 percent, in Michigan James Blanchard got 97 percent and Wisconsin's Anthony Earl got 98 percent.

But it was in the South where black voters flexed the most muscle, helping white Democrats oust conservative Republicans from House seats in Alabama, North Carolina and South Carolina. In Birmingham, hard-hit by steel layoffs, blacks swarmed to the polls to help retire freshman Rep. Albert Lee Smith Jr. (R), a diehard Reagan supporter.

Many white Democrats, however, could not bring themselves to shed tradition by backing even a moderate black like Mississippi's Clark. While Sen. John C. Stennis (D) pulled 84,000 votes from the new Delta district, 13,000 split their ticket and voted against Clark.

Interestingly, Clark's strategists had avoided a highly visible effort to turn out black voters to avoid scaring whites.

Yet several white victors this week courted the black vote aggressively. "White politicians are finally maturing and recognizing the potential of the black vote," Williams said. "They are learning how to count."