While Democrat Henry E. Howell was mentioning the names of his friends in the White House, Republican John N. Dalton quietly had discovered an ally in the federal bureaucracy: the postman.

At a time when much of the public's attention on campaign spending has been focused on television advertising purchases, the Dalton gubernatorial campaign appears to have earmarked as much as $250.000 for what is an apparently unprecedented direct-mail effort.

By the time of Tuesday's election for governor, the Dalton campaign probably will have mailed about 500.000 letters to the state's 2 million workers - or one letter for every four registered voters - according to sources close to the Dalton campaign. The Dalton campaign. The Dalton staff is reluctant to discuss details of the mailing operation, but its size became apparent today when Dalton released his latest campaign finance report.

Dalton's postage bill alone already has totaled $124.889.62 and his fees to National Direct Mail Service, a Washington firm that has handled two of his massive computerized mailings, cost $103.396.45 more. In addition, there are printing and other advertising costs related to the mailings.

Howell, by comparison, has spent relatively little money on direct mail and only two weeks ago made his first direct-mail bid for money. His mailing, considered highly successful by the Howell staff, totaled about 17,000 letters.

Dalton's campaign manager, William A. Royall, conceded today, in response to questions that the mailings are largely responsible for Dalton's record number (14,508) of small contributors. The mailings have raised more money "than we ever dreamed up." Receipts are running 50 to 80 per cent ahead of projections, he said.

Never before has a candidate relied so heavily on direct mail in a state election and never has the mail been so controversial, many politicans here say.

Howell has charged that the author of Dalton's first massive mailing was "meaner than a junkyard dog" and has likened some of the letters to "Nazi propaganda."

Dalton's staff has insisted the letters accurately portray Howell's positions, but last week after a second massive mailing. Howell again complained of "slick, sly letters" from Dalton, which Howell said distort his positions and "have caused confusion through deceptive and deceitful words."

Oratroy aside, there is no dispute that the letters have already had a major impact on the campaign. Dalton's staff won't say precisely how much money the letters have produced, but his expense reports indicate that 31 per cent of his $1.6 million in campaign gifts have been in amounts of $100 or less. Much of that has been raised through the direct mail letters.

Mail has become such an integral part of the Dalton campaign style that Virginians ranging from telephone bank volunteers to major contributors are likely to get a letter from the candidate. In addition the massive, computerized mailings are targeted to sections of the state and likely conservative precincts, Royall said.

Between 25 and 30 per cent of the mail has been aimed at the Washington suburbs, a region Dalton has called crucial to his campaign. Television adds are more expensive in Northern Virginia than in any other part of the state and state candidates say they have difficulty reaching voters there with their campaign messages.

Dalton's letters to the region have featured his positions on Metro, water, and transportaion. His most recent letter, which carried the letterhead of the State Capitol, omitted a paragraph in Northern Virginia attacking Howell's stand on the right-to-work law that was in a similiar letter mailed to residents of the Richmond area. A version of the letter mailed elsewhere also contained strong language attacking Howell as appearing "more interested in seeming to be all things to all people."

The massive computerized mailings contained pledge cards seeking donations and business reply envelopes that are coded. That allows the Dalton campaign to track its receipts, but Royall refused today to give precise figures on the mailings. "The campaign's not over." he said. "I don't want to be revealing any of my strategy."

A Democratic strategist, who asked not to be named, said today that Dalton's mailings have been effective because the letters allow Dalton to make a "tough" charge against Howell but give the Democrat no quick chance to reply to the charge. "If you call a press conference to denounce the charge, you may be speaking a week after the letter was mailed and by that time the letter has already had its impact and is out in the trash," he said.