Virginia Gov. Mills E. Godwin, calling Democratic nominee Henry E. Howell a threat to the state's economic welfare, said today he will campaign aggressively for Republican candidate John N. Dalton.

"The question before Virginians," he said, "is whether or not we can continue our course of business support and preserve a favorable business atmosphere. That is why I have spoken out for Mr. Dalton and will continue to do so."

Although the Republican governor said today he would campaign harder for Dalton than earlier planned, he said he will vote a split ticket in the Nov. 8 election. He will support the Democratic candidate for attorney general, Edward E. Lane, "because of a personal friendship of a quarter century that transcends political matters," he said.

Godwin said that although he will not vote for the Republican attorney general nomines, A. Marshall Coleman, he will support his party's candidate for lieutenant governor, State Sen. A. Joe Canada of Virginia Beach. But Godwin said he will not campaign actively for Canada.

A more active role for Godwin in the Dalton campaign holds out the promise of a new political battle between Godwin and his arch fos, Howell.

Howell rose to prominence in the 1960s as a leader of moderate-liberal opposition to the conservative organization headed by the late governor and Sen. Harry F. Byrd Sr. Godwin was the last Democratic governor to be elected with the backing of the Byrd organization when he served from 1965-69,. He left the Democratic Party after Howell allies took control of the state political organization in 1972.

Godwin strongly endorsed Dalton, now the state's lieutenent governor, when Dalton announced his candidacy in March but has not campaigned extensively for him since then. Many party and campaign officials thought he had decided to concentrate his energies on winning voter approval of the $125 million bond issue for colleges, prisons and other state facilities and to make only a few appearances for Dalton.

Shortly after Godwin announced his campaign intentions at a Capitol news conference, both Howell and state Democratic chairman Joseph T. Fitzpatrick called on him to refrain from partisan stumping, which they said could hurt chances of bond issue approval.

At an Alexandria campaign appearance, Howell recalled his 1973 defeat by Godwin and professed dismay at what he called Godwin's "mission" to deny him the governor's office.

"He ran in 1973 to save the state from Henry Howell," Howell said. I have nothing against Gov. Godwin . . . But he has had this mission for a long time."

Godwin has in the past denied that he ran for a second term as a Republican merely to keep Howell out of office. However, at today's news conference, he came close to contradicting those denials when he released a list of 49 former Democratic Assembly members who have endorsed Dalton.

"They are putting the Commonwealth of Virginia and her welfare above the interests of any party," Godwin said. "I ran in 1973 because I felt the welfare of Virginia is far more important than either the Democratic or Republican Party."

Howell's alliances with labor union and his populist attacks on big business, especially banks, utilities and insurance companies have always been portrayed by Godwin, Dalton and their supporters as a potential threat to Virginia's economic growth.

Godwin is one of the most popular politicians in Virginia and he can serve as Daltons's link to the conservative Democratic establishment, with which Howell has been so long at war. Dalton is as conservative as Godwin, but campaign officials agree that he lacks the personal standing with this group that the governor has.