The Liberal Party in Honduras has won a clear upset victory in elections for a Constituent Assembly that will formally end eight years of military rule.

The Liberals' defeat of the better-fiananced and Army-backed Nationalist Party in yesterday's election held out the hope that the country could effect political change without the political violence that as plagued some of its Central American neighbors.

With most of the ballots counted, the Liberals were expected to pick up as many as 38 of the 71 seats in a Constituent Assembly that will frame a new Honduran constitution.

The Liberals apparently have garnered more than 52 percent of the vote, about 8 percent more than the Nationalists, who had been preelection favorites to win a majority of assembly seats.

In 1963, a Liberal government was overthrown and the party has been out of power ever since, with either soldiers or their conservative allies in the Nationalist Party holding the office of president.

With 38 assembly seats, the Liberal Party would have the power to name a member of their group president when the assembly convernes in July. The Liberals were expected to have a majority of six or seven seats over the Nationalists. The National Innovation and Unity Party, a new and relatively weak reform-minded coalition, finished a distant third.

During the 1970s, the military and the Nationalists were repeatedly stained by allegations of widespread corruption, including graft, receiving bribes from multinational corporations and narcotics trafficking. A key Liberal slogan was to "throw out the thieves."

The election results that came in last night and today are a clear rejection of the military-Nationalist regime, but what exactly the elections will mean for the future of the 3.5 million people in this poorest of Central American countries remains an open question.

The Liberal leadership is mostly composed of conservatives who favor economic, political and social reform policies their last government started 20 years ago.These policies may not be adequate to the demands of today's Central America or the needs of a largely illiterate and underdeveloped nation bordering on the unrest of Guatemala, the revolution in El Salvador and the revolutionary regime of Nicaragua.

With the exception of the National Innovation and Unity Party, other reformist or radical organizations ranging from the centrist Christian Democrats to the Communists were excluded from yesterday's election.

These parties have never shown significant strength in Honduras and their government-stifled calls for abstention yesterday went generally unheeded. But most of the country's politicans, including even the conservative Nationalist and the Liberal leadership now say the exclusion was a mistake.

Besides writing a new consitiution, the Constituent Assembly will have the power to convert itself into a legislative assembly or schedule legislative elections. It may appoint a president or set presidential elections.

A Liberal majority may effectively bar more reformist or leftist parties from meaningful political participation for the next several years, regardless of technical changes in the electoral law.

Several Honduran observers believe the Liberals may be tempted to name one of their own as president because their current party leader, Roberto Suazo Cordova, is not thought charismatic enough to win a direct popular election. It is also though that his badly divided party, which united to win seats in the assembly, might not stay united in a nationwide campaign to make Cordova president.

There is, however, considerable pressure from the armed forces for the new Constituent Assembly to go ahead and call a second round of national elections for a congress and a president. Since the Army will continue to run the country for the next few months, and always remain at least in the background of Honduran politics, its opinion is not taken lightly.

The United States, another decidedly infulential force in Honduran politics, has also come out strongly in favor of direct presidential and congressional elections.

The Liberals have yet to make a decision or a clear public statement on the issue, saying they will leave the question up to a party convention to decide.