Republican John N. Dalton and Democrat Andrew P. Miller have been marching through the executive suites, law offices and private clubs of Virginia's conservative business community for the past few months waving the same red flag - the prospect of Henry E. Howell in the governor's office.

Howell's past attacks on big business are enough to galvanize business leaders behind anyone oppoing him, but this year they are clearly torn between backing Miller against Howell in the June 14 Democratic gubernato rial primary, or starting immediately to build support for Dalton in November general election.

Among those who have chosen to support Miller, there is no question which course they will take if he falters in the primary. Even Miller's state finance chairman, Richmond insurance executive E. Massie Valentine, said in an interview that if Howell becomes the Democratic nominee, "You'll see me the next day holding John Dalton's hand."

Such a statement by the chief fund raiser for a Democratic candidate would set off political turmoil in some states, but on Richmond's Main Street, the symbolic artery of the state's business community, party lines have become increasingly blurred over the last 25 years.

The leftward lurches of the State Democratic organization in 1958 and 1972 have made it respectable for the once heavily Democratic business leadership to back conservatives in both parties.

Just as Miller's chief fund raiser stands ready to aid Dalton if Howell wins, Dalton's best known business supporter, Thomas C. Boushall, honorary board chairman of the Bank of Virginia, is working just as hard for Democratic attorney general candidate Edward E. Lane of Richmond.

Dalton and Lane are easily indentifiable as conservatives who suit the politics of the Virginia business establishment. Miller has a more moderate image, but his standing with business interests has been helped by his unquivocal support of the state's right-to-work law banning compulsory unionism and his campaign opposition to collective bargaining for public employees.

Miller recently resigned after seven years as attorney general. Dalton is now the state's lieutenant governor from 1971 to 1974.

Despite the fact that his advocacy of the consumer and utility rate payer has given him an antibusiness image, Howell is not entirely without business donors.

Thet include Sydney Lewis, president of Best Products Co., and David Kinney, the Northern Virginia lawyer and real estate investor who once ran unsuccessfully for Congress in the 10th District. Lewis was a major contribution to both Howell and Miller. Like other Howell donors, the liberal outlook of Lewis and Kinney set them apart from the Virginia business establishment.

In this campaign as in past ones, Howell is looking more to labor unions than to businesses for campaign contributions.

The contest between Miller and Dalton for the hearts and financial support of big business started in earnest around the first of the year when Dalton was still an unannounced candidate and Miller was bringing his primary organization up to full speed.

"We could see the Miller people were making an aggressive effort for business support," Dalton's campaign director, William A. Royall, said in an interview. "We felt we had to counter it before it was too late, and we were very successful."

Dalton, Royall and Dalton's finance chairman, Richmond investment banker Walter W. Craigie Jr., began an intensive round of personal meetings with business leaders. Some were held in corporate offices, some over lunch at such executive retreats as the exclusive Commonwealth Club in Richmond.

By early February, Dalton appeared to be gaining ground. His forces quietly convened a dinner of 200 potential big donors at a motel near the Richmond airport and presented the Dalton fund-raising strategy in the presence of National Republican Chairman Brock.

Dalton, Royall and Dalton's finance chairman, Richmond investment banker Walker W. Craigie Jr., began an intensive round of personal meetings with business leaders.Some were held in corporate offices, some over lunch at such executive Commonwealth Club in Richmond.

By early February, Dalton appeared to be gaining ground. His forces quietly convened a dinner of 200 potential big donors at a motel near Richmond airport presented the Dalton fund-raising strategy in the presence of National Republican Chairman William Brock and former GOP Gov. Linwood Holton. Gov. Mills E. Goodwin was scheduled to attend, meeting with President Carter's energy adviser, James Schlesinger.

Holton underscored the political significance of financial support from Main Street recalling in a speech that his 1969 campaign was rescued from a massive layoff of workers weeks before the election by a public endorsement by business leaders. The endorsements turned on a stream of contributions that helped Holton beat William C. Battle, like Miller, a moderate Democrat.

The Dalton organization made it clear at the dinner that it expects business interests to play an equally-important role in his campaign.

Royall presented a financing plan that placed primary importance on big business givers, especially in the Richmond area. Of the $1.3 million projected budget, the Dalton organization expects to raise almost $800,000 in contributions of $1,000 or more. Out of 10 congressional districts, the Republicans are expecting to raise 27 per cent of the Dalton contributions in the Third District, which includes Richmond and its suburbs.

These ambitious fund-raising goals were given a degree of credibility when Lawrence Lewis of Richmond, a major contributor to recent Virginia Republican campaigns, praised the Dalton organization as one of the best he has seen.

Not long after the Dalton dinner, Miller supporters staged what appeared to be a hastily executed counter-demonstration of business support with a luncheon at the John Marshall Hotel here. Invitations were issued on a Wednesday for the next Monday and the regrets outnumbered the guests. Nevertheless, Miller campaign director Walter A. Marston said 200 business people showed up.

Big dinners and luncheons have been the exception in the Dalton-Miller contest, however, and most of the commitments to both sides have been won in private meetings. "There has been a tremendous battle going on," Miller fund-raiser Valentine said. "For a while, it looked like a Mexican standoff, but now I think the balance seem to have enough charimsa. But he is tipping our way."

In interviews, the executive who have been wooed by both sides agree that the issue has been whether Dalton can be elected in a race against Howell. Although he is preceived as more conservative than Miller, business leaders who want a sure bet against Howell are worried that he is not forceful enough.

"Conservatives had doubts about his electability," Boushall said. "He didn't see to have enough charisma.But he turned that image around at his announcement. With 600 people in that ballroom . . . he was excellent. It's been very encouraging to see him shine."

One executive who could not be persuaded that Dalton is the best bet against Howell is J. Howard Cochrane, who started as a self-employed truck driver and built the Richmond-based Overnite Transportation Co. He was wooed heavily by the Dalton camp.

"I see Dalton as being a shade more conservative that Miller," he said, "but I share the fear that he just isn't strong enough to make it."

On the other side, J. Clifford Miller, president of a wood-container manufacturing company, endorsed Dalton after being personally visited by both candidates. Miller, who is not active business supporter of the old Byrd Democratic organization. Explaining the goals of businessmen supporting Dalton, he said, "We have been trying to elect conservatives, not moderates."

Both sides clearly lost supporters in close decisions, like the one made to support Miller by former Richmond Del. Thomas P. Bryan, a vice president of the Miller and Rhoads department store. "I think either one would make a good governor," Bryan said. "But I believe Andy will make a really fine governor."

Nailing down business support before the Democratic primary is viewed as important by Dalton supporters because they know it will be hard for business leaders who back Miller publicly to switch to Dalton if Howell wins the primary.

John Ambler, an Ashland lawyer and cousin of Richmond businessman james Ambler, who supports Dalton, pondered the switching problem was he sat in his law office last Thursday.

"I'm sitting here looking at some Miller fund-raising papers right now and trying to make a decision," he said. "You can always vote as you wish in the general, but if I get out and raise money for Miller now, then I could never do anything for Dalton in the fall."

If Miller is Dalton's opponent in the general election, then clearly the motivation, for business donors will be lower than it is now with Howell as a candidate.

"I like Henry personally, of course, said Valentine, "but the kinds of things he says make it easier to raise money for his opponent from people interested in business growth."