Virginia's delegates to the Republican National Convention, who consider themselves among the GOP's most conservative, proved it today by strongly supporting Jack Kemp for the vice-presidential slot.

The conservative Kemp won 31 votes from the 51-member delegation in a straw poll this morning, far out-distancing George Bush, who finished second with 10 votes. Most of Kemp's support came from delegates elected at the district level, while Bush won backing largely from state officials and other members of the party's hierarchy.

The poll, one of at least a dozen taken by various state delegations today, is giving impetus to a Kemp drive, whose leaders include Virginian Guy O. Farley Jr., a Warrenton lawyer who pushed today's straw poll and is circulating petitions for Kemp.

"It's just another indication that Kemp is strong with the people who really count -- the grass-roots volunteers who ring doorbells and do the work that will get Ronald Reagan elected," said Jade West, a delegate from Arlington.

Gov. John N. Dalton and AttorneyGeneral J. Marshall Coleman both supported Bush in the poll. Dalton said later that Bush's foreign policy experience and strong showing in some of the primaries against Reagan made him "the strongest candidate."

But John Alderson, Reagan's Virginia campaign coordinator and a Kemp backer, said major criteria should include picking someone from a major electoral state not already in Reagan's column. Kemp, a U.S. representative from New York, fills that bill, he said.