Starting a new magazine is a heady venture, admits writer Quincy Troupe. But the esthetic and social rewards are worth the risk, he says.

And so Troupe, 35, is off and running and editing The American Rag, a magazine he wants to fully reflect all the various opinions, multi-cultural rhythms and ideas of the different American ethnic groups.

The first issue, on the newsstands since September, has fiction by Gabriel Garcia Marquez, Budd Schulberg and Ntozake Shange, poetry by Victor Hernandez Cruz, Pedro Pietri and Lucille Clifton and interviews of Toni Morrison and Norman Lear.

Future issues will contain pieces by Octavio Paz and several other Mexican writers, an interview of John Cheever and poetry by Denise Levertov.

"I think people are ready for a serious general-interest magazine," Troupe says, unfurling his 6 feet 2, 210-pound frame. "I rush to the newsstands looking for basketball books, but I don't even bother looking for other magazines. I used to rush to pick up Evergreen Review or Black World.

"We're trying to reach a balance. We want to reflect all the Americas. Our goal is to have 200,000 circulation in two years, and we can do that because we're working hard, and there's a lot of interest in what we're doing."

The magazine's audience, Troupe says in his rapid-fire speech, is the 18-45 age group. "We want the people formed and shaped by the '60s, people who still want change," he smiles. "There's a multicultural movement right under our noses and a lot of us don't know about it."

Troupe says a year's sabbatical he concluded last week convinced him of what he calls "multi-cultural rumblings." He spent six months in northern California finishing a novel and a book of poetry (the latter, "Snake Back Solos: Selected Poems, 1969-1977," was just published).

The other six months he spent traveling around the country, reading his poetry and talking with people in Georgia, Mississippi, Michigan, Idaho, Arizona, Colorado and other places about what was on their minds.

"Everybody has gone to the end of the rope and they think it's time for a change," he says as he furrows his brow and purses his lips in meditative fashion.

"I was in Los Cruces, N.M., and this farmer used to pick me up every morning, and we'd go out in the woods and talk about what was wrong with the world.

"A lot of people understand what I'm talking about, and a lot of them are white people.

"I talked to blacks, whites, Chicanos, native Americans."

Troupe's fascination with different ethnic groups and Latin American and Asian literature started when he lived in Los Angeles in the mid-'60s and was a member of the Watts Writers Workshop (started by Budd Schulberg).

The writer may have picked up some appreciation of Latin American culture as a youngster when his father, Quincy Troupe Sr., a catcher in the old Negro baseball leagues, would take the family to Mexico, Cuba and Venezuela for winter baseball barnstorming tours.

However, Los Angeles was where Troupe decided to become a writer (in college at Grambling he had been a basketball standout along with Willis Reed, who went on to star for the New York Knicks, but a knee injury in the Army cut short his pro prospects).

In California, he edited his first book, "Watts Writers and Poets." Afterward, he taught at Ohio University and edited "Confrontation," a literary quarterly. Next came "Giant Talk," an anthology of Asian, African and Latin American writers he edited.

Troupe also was a leader in the black poetry movement of the late '60s and early '70s. Like many young Afro-American writers, he traveled a freshly grown circuit reading his work and discussing his craft.

Looking back on that period, he says it was "relevant and necessary." He adds: "In the '60s, black poetry was concerned with white people. Now it's more personal. People still turn out in large numbers in New York. We had 2,000 people at Columbia (University) recently to hear Toni Morrison, Gwendolyn Brooks and some others."

As heady as that period was, the present is comparable in excitement for him, he says.

Troupe is teaching American and Third World literature at the College of Staten Island and directs special projects and a poetry workshop at the Frederick Douglass Center in Manhattan.

And then there's the magazine. It's moving slowly, he says. Money has come from the New York State Council on the Arts and several private donors.

"We're not trying to do this very quickly," he says, taking a deep breath. "One thing for sure: Writers are interested. I have enough stuff for five or six issues to come."

The American Rag made its Washington debut at a party last night at The Last Hurrah. Among the 400 guests were entertainer Oscar Brown Jr., Effi Barry, wife of Mayor Marion Barry, Rep. John Conyers Jr. (D-Mich.), Larry Neal, executive director of the D.C. Commission on the Arts and Humanities, and Myra Sklarew, chairman of the American University English department.