* Communist party to set future course at April congress
* Proposals recommend changes, but do not scrap socialism
* Experts see good first step but say wider changes needed (Recasts, adds quotes)
By Esteban Israel
HAVANA, Nov 9 (Reuters) - Cuba's ruling Communist Party will tinker with the island's socialist system at a party congress in April, but its underlying task is to ensure the system's survival when the current, aging leaders are gone.
Whether the proposed changes detailed in a document released by President Raul Castro on Monday will be sufficient to achieve that goal remains an open question.
The 32-page "Guidelines of Economic and Social Policy" that will guide the congress paints a picture of a future in which Cuba promotes foreign investment, expands the private sector and dutifully pays off its debts.
But it also makes clear that all reforms will come in the context of the socialist system installed half a century ago after Fidel Castro took power in a 1959 revolution.
"The economic policy in the new phase will correspond with the principle that only socialism is capable of overcoming difficulties and preserving the gains of the revolution, and that in the updating of the economic model, planning will be paramount, not the market." it said.
President Castro has already begun a number of the proposed reforms, including his groundbreaking announcement in September that the government will trim half a million jobs from its payrolls by March and issue 250,000 self-employment licenses.
His overarching goal is make the island's troubled economy solid and self-sustaining by increasing productivity and reducing state expenditures.
The proposals before the party congress include the elimination of the monthly food ration Cubans receive, a symbol of decades of state paternalism and a particular target of Raul Castro, who says handouts have discouraged productivity.
There are provisions for bank credits for the newly self-employed, but also provisions that require them to pay taxes to finance public spending.
FOREIGN INVESTMENT
And the authorities will look to improve the country's international credibility "through the strict fulfillment of contract commitments."
Cuba's standing with the international business community has been damaged over the past two years as a cash crunch forced the freezing of Cuban bank accounts held by foreign businesses and of payments to many of them.
The guidelines propose "to continue encouraging the participation of foreign capital in Cuba, complementing national investment in those activities of interest to the country."
The document mentions, for example, the development of golf courses, marinas and luxury condominiums to attract wealthier visitors to the Caribbean island.
The changes are significant for Cuba, which is one of the world's last Communist countries, but many experts say greater economic opening may be needed to achieve Castro's goals.
"What they are talking about now is a good first step, but ultimately it seems like they will have to open their economy more like China and Vietnam have for socialism to work," said a diplomat based in Havana.
Before that, said another, Cuba needs to fill gaps in its economic infrastructure to have a shot at success.
"They don't have many factories, they don't have money, they don't have training. They'll need all of that and more to make a go of it," the diplomat said.
The congress is where Cuba's only legal political party sets direction for the country, supposedly for the next five years, although it last met in 1997.
The April gathering is particularly important because it will be the last for the generation that fought the revolution and has held on to power, hewing hard to communist ideology.
President Castro, 79, took office in 2008 after older brother Fidel Castro, 84, ruled the island for 49 years and finally resigned due to ill health. The elder Castro remains head of the Communist party.
There has been little discussion in Cuba of political reform to accompany economic changes. Cuban expert Arturo Lopez-Levy, at the University of Denver, said "there is not a crisis of governability in Cuba" because the Communist party has no serious rival.
But he said the party could become its own worst enemy if it is too rigid. "If the Communist Party has an enemy over the long term, it's the force of some of its dogmas and convictions," he said. (Editing by Jeff Franks and Todd Eastham)