Grenadians overwhelmingly elected a U.S.-backed coalition today to return this little island to parliamentary government 13 months after U.S. soldiers smothered the remains of its shattered revolution.

The New National Party of veteran politician Herbert Blaize won at least 10 seats in the 15-member House of Representatives and was headed for victory in three or four more, according to a preliminary election commission tally of about 90 percent of the vote.

The party, forged under the guidance of Caribbean leaders who worked with Washington in last year's invasion, has been singled out by U.S. diplomats in private conversations as the best vehicle to return Grenada to stable government after the tumultuous decade since independence from Britain in 1974.

Blaize's chief rival, former prime minister Eric Gairy and his Grenada United Labor Party, trailed far behind with no sure victories and a lead in only one district. The outcome constituted a sweeping repudiation of the mystical leader who was overthrown by Maurice Bishop in 1979 after gaining international notoriety by urging the United Nations to investigate unidentified flying objects.

Blaize is scheduled to be sworn in for a five-year term as prime minister within days, possibly Wednesday, according to his jubilant supporters. Blaize, 66, remained secluded on his home island of Carriacou, a tiny Grenadian dependency whose telephone system was out of order. But he was expected in St. George's Tuesday to claim his triumph.

The ceremony will mean automatic dissolution of an Interim Advisory Council that has been running island affairs under Governor General Paul Scoon since a dissident revolutionary faction killed prime minister Bishop along with his closest followers and opened the way for the U.S. invasion on Oct. 25, 1983.

The Maurice Bishop Patriotic Movement, headed by former government officials Kendrick Radix and George Louison, was put together by remnants of Bishop's New Jewel Movement that ruled from the overthrow of Gairy until its disintegration last year. The movement was defeated in each of the 12 districts in which it fielded candidates, according to the preliminary results. The showing was seen as a demonstration of strong revulsion still felt by most Grenadians over the New Jewel Movement's degeneration into violence.

Keith Mitchell, secretary of the New National Party favored by the Reagan administration, said earlier in the day that a high turnout throughout the 133-square-mile island of nutmeg plantations and arcing beaches favored his party. Gairy, associated by many Grenadians with spiritualism and corruption, retains appeal only among a core of poor plantation workers and fishermen who benefited from the patronage of his party and labor unions, he said.

"If we get a heavy turnout, he Gairy is in trouble," said Mitchell, 36, a former statistics professor at Howard University who was a candidate for one of the 15 seats in the House of Representatives. "For him to win, there has to be a light turnout."

The Grenada Civic Awareness Organization, a nonpartisan group that has received funding from American sources, arranged for taxis and minibuses to ferry voters to the polls, according to government spokesman Jerome Romain. Bernadette Williams, 22, a New National Party volunteer at one seaside polling place, said she was checking voters' names off a central list and sending out the taxis assigned to her district to bring in likely supporters who had not yet cast ballots.

Taxi drivers, who said they were getting $130 for the day, said they were picking up whoever needed rides, regardless of party affiliation. But Williams was the only party worker helping dispatch taxis from her polling place at Happy Hill about three miles north of the capital.

The National Republican Institute for International Affairs, which is linked to the Republican Party, has acknowledged providing $20,000 to the Grenada Civic Awareness Organization. A second American group, Conservative Youth, said it raised funds for direct help to the New National Party. In addition, the Free Trade Union Institute, tied to the AFL-CIO, provided funds to a Grenadian labor group and funded purchase of get-out-the-vote posters.

One bumper sticker that a diplomatic source said was funded by the Free Trade Union Institute caused a ripple among island politicians because its message -- "Vote Dec. 3" -- included a star inside the "o" of "vote." The star is the symbol of Gairy's party, and volunteers had to carve the star out of the sticker before it could be distributed.

Gairy, who returned from exile in San Diego three months after the U.S. invasion, had called for a permanent U.S. military presence on the island, along with a British naval base. About 250 U.S. Army troops remain, the last of an invasion force that totaled 11,000 on sea and land at its peak, but they are scheduled to leave next year, when Grenadian police are trained.

Despite his effusive praise for President Reagan's intervention, Gairy has been treated by U.S. officials as an embarrassment. In private conversations, they predicted that a victory by Gairy's party could lead to reassessment of the U.S. commitment to economic development here, including a $57.2 million aid program.

During his years in power, Gairy frequently reminds visitors, he enjoyed good relations with the United States. But Gairy's return to office now, given his former administration's reputation for brutality and venality, would tarnish the Reagan administration's politically popular military action and perhaps provoke a resurgence by Bishop's leftist followers, U.S. officials say.

Gairy's notoriety abroad nevertheless did not diminish support among a swath of Grenada's 90,000 inhabitants whose families have received personal help from Gairy or his party's labor union movement.

"If Gairy gets back, he'll be a changed man," said Fitzroy Woodruff, an island laborer. "He'll learn from his mistakes."

Voters at a polling place in the Rockside Disco in northern St. George's, for example, shouted support for "the star" and predicted victory by "Uncle Eric," calling him the only candidate who can protect the island against a return to violence.