Twenty-five years ago Soviet support for Cuba was resolute almost to the point of war, but the United States now sees a chance to drive a wedge between Moscow and Havana over economic and Central America policy.

Cuban President Fidel Castro, who is said to have urged former Soviet leader Nikita Khrushchev to bomb the United States at the height of the 1962 Cuban missile crisis, plays host Sunday to reform-minded Kremlin chief Mikhail Gorbachev.Castro disagrees with Gorbachev's perestroika (restructuring) program, which he believes could threaten the "ideological purity" of his 1959 revolution.

The Cuban leader clings to the Marxist-Leninist doctrine of centralization, which U.S. experts say has resulted in a tattered economy so dependent on Soviet aid that it re-exports Soviet oil to gain hard currency.

U.S. analysts say Gorbachev, faced with his own domestic troubles, is likely to press Castro to open up his economy so Moscow can save some of the estimated $5 billion a year it sends to the Caribbean island.

They say Castro will argue against easing military aid to Nicaragua and leftist guerrillas in El Salvador.

"I believe there will be a lot of bargaining going on, perhaps even some screaming and yelling, which is characteristic of Fidel Castro's style even with the Soviet leaders of the past," says Jiri Valenta, a Soviet and Cuban expert at the University of Miami.

The United States hopes to profit from any Soviet-Cuban discord over aid to Nicaragua and Salvadoran guerrillas engaged in a nine-year war against the U.S.-backed government there.

But the experts believe the Bush administration will take a cautious approach toward Cuba for the present, refusing to negotiate the status of the U.S. base at Cuba's Guantanamo Bay or lift an embargo against Cuba in place since 1963.

Bilateral problems will be limited to such issues as immigration and drug trafficking, they say.

Elliott Abrams, who was Ronald Reagan's assistant secretary of state for inter-American affairs, predicts the Bush administration will raise the level of discussion on Soviet aid to Nicaragua in contacts with the Gorbachev government.

"I suspect Central America will prove to be an item of contention between the Soviets and the Cubans. A U.S.-Soviet agreement on Nicaragua could be very troublesome for Castro because what is left for his international role?"

Vice President Dan Quayle said: "Cuba is in our hemisphere and Latin America is in our backyard, and the Soviet Union continuing to finance these governments that export revolution beyond their countries is destabilizing. It is not helpful to U.S.-Soviet relations."

He says if Gorbachev wants to improve Soviet relations with the United States he should be prepared to see support for Cuba and Nicaragua eliminated.

For Castro to gain desperately needed hard currency, analysts believe he will have to encourage tourism from the United States. But they doubt Bush will lift the embargo against Cuba.

Susan Kaufman Purcell, vice president for Latin American affairs at the Americas Society research institute in New York, says she believes Gorbachev will urge Castro to improve relations with the United States out of economic necessity.

"This would be good for both Castro and Gorbachev because it would allow the maintenance of the military security relationship between the two countries," she says.

But she doubts the United States will be prepared to cooperate.