For six of the last seven years, Fairfax County Supervisor Thomas M. Davis III has tried to do what might seem a very simple thing: to convince his colleagues on the county board that the pamphlet sent to county households announcing fall bond referendums should be presented in a pro-con format.

Despite his lobbying, Davis has been voted down consistently, and the pamphlets have included dry and ostensibly neutral descriptions of the purposes and effects of the county's bond proposals.

Yesterday, he tried again -- and won on a 5-to-4 vote.

No one was more surprised than Davis. "I didn't even work it this year," he said.

Davis' victory came after Supervisor T. Farrell Egge, a Republican who opposed the proposal last year, switched his vote to support a pro-con format.

Egge's switch was not at Davis' behest. Rather, it was a product of a parochial concern:

Egge said the $146.1 million school bond proposal that will appear on ballots this fall would not provide for enough construction in his Mount Vernon District in southern Fairfax County, and he wants the con side of the bond pamphlet to make that clear.

"Mount Vernon is getting the short end of the stick," he said. About $6.1 million of the bond issue would go to projects in Mount Vernon District.

Said Davis: "I'll take my votes however I can get 'em."

In other action yesterday, the board:Voted to ask Gov. Gerald L. Baliles to reconsider the Virginia highway board's decision to expand the hours during which car pool restrictions apply on I-66 inside the Capital Beltway until another study is performed to prove the need for the restrictions. Asked the county staff to "research the advisability" of suing the District government or intervening in a lawsuit to limit the inmate population at the District-run Lorton Reformatory.

After the vote on Davis' pamphlet proposal, the board members who for years have been successful in quashing his idea were miffed.

"The information we've sent out is not advocacy information," said Supervisor Nancy K. Falck, a Republican. "It's just plain information, as neutral information as we possibly can, and we just let the voters decide."

Board Chairman John F. Herrity, a Republican, also opposed the idea of a pro-con format, declaring that in past years the pamphlets have laid out the bond information "as objectively as possible."

The real trouble may come later this summer, when the board tries to decide the precise wording of the pro and con sides of the pamphlet, which will advertise the school bond as well as a separate $20 million proposal for projects in the county's aging neighborhoods.

A draft of the pros and cons will be written by a citizens committee appointed by the board. The draft then will be forwarded to the board for revisions and final approval.

Voting with Davis for the pro-con proposal were Supervisors Audrey Moore (D-Annandale), Elaine McConnell (R-Springfield) and Katherine A. Hanley (D-Providence) and Egge.

Voting against the proposal were Supervisors Joseph Alexander (D-Lee), Martha V. Pennino (D-Centreville), Herrity and Falck.