The Atlantic Coast Conference will decide today whether to adopt a 30-second shot clock and the three-point field goal to increase scoring in its conference basketball games. According to sources, one will not be accepted without the other.

Athletic directors from the eight schools, conducting their spring meetings in Myrtle Beach, S.C., will vote this morning on whether to accept the changes. Majority approval is needed; then the athletic directors would or would not recommend the changes to the eight faculty advisors.

The shot clock would be turned off in a game's last five minutes. Three points would be awarded for any shot beyond 19 feet.

A shot clock alone, it is thought, would not be enough to speed up games because teams could sag back, as they have done the last few seasons, into zone defenses for the full 30 seconds. But if three points are awarded for medium-range shots, teams will be forced to defend aggressively.

The shot clock and three-point shot have been the focus of debate by ACC coaches and athletic directors the last three days. The conference received considerable criticism last season because its teams scored fewer points than those of any other major conference in the nation. The ACC championship game, between North Carolina and Virginia, turned into a debacle of inactivity.

In late March, at the ACC coaches' meetings, a 45-second clock was proposed. Sunday, coaches and athletic director decided on 30 seconds.

Dean Smith, coach of national champion North Carolina, has said he favors the clock and the three-point field goal. Of the eight coaches, only Duke's Mike Krzyzewski said before the meetings that he opposed a shot clock.

Maryland Coach Lefty Driesell said repeatedly last season that he favored some type of shot clock to speed up games and make them more exciting.