Organizers of the Eleventh International Sculpture Conference have issued a "firm list" of the 49 American artists set to participate in the city-wide sculpture show which, as part of the conference, will open here June 4.

Louise Nevelson, Isamu Noguchi, Tony Smith and Claes Oldenburg (who will plunge a giant trowel into the construction site in front of the District Building) are among the sculptors listed. Alice Aycock, Larry Bell, Ronald Bladen, William Christenberry, Jackie Ferrara, Duane Hanson, Ed Kienholz, Rockne Krebs, Ed Love, Martin Puryear, Eric Rudd, Michael Singer and Anne Truitt also have agreed to display their works at the Pension building, the Corcoran's Dupont Center or at Various outdoor sites around town.

"These artists have agreed to show," said conference director David Furchgott, "and we have agreed to finance their showings in Washington."

Materials to be used by participating sculptors include bronze, wood, marsh grass, laser beams, sound waves, steel and bamboo. One of the sculptures to be shown, a miniature village by Charles Simonds, will be shoe-box size. Others will be huge.

Works by 40 foreign artists also will be shown. Their names have yet to be announced.

Furchgott expects some 4,000 people -- sculptors, curators, teachers, critics, dealers and collectors -- to attend the conference which closes here June 7. The budget for the meeting, he said, will be $666,000, most of which, he added, is not yet in hand.

About $110,000 of that amount, Furchgott said, will be spent to install the works of the 49 American sculptors. Whether that sum will be sufficient for a 49-object exhibition is unclear. The fabrication of some site-specific works is expected to cost more than $15,000.

In addition, the crating and insuring of sculpture is a costly business because a number of the larger works, for instance the Noguchi, weigh many tons and must be shipped to town. And finally, erecting sculptures in public spaces is notoriously expensive.