Forget about Skylab. Silver Streamers, Blossoms after Thunder and Sparkling Delights are ready to rain down tomorrow night in the annual fireworks extravaganza at the Washington Monument.

This year, however, instead of the ever-zestful George Zambelli, producer of the Mall show for 16 of the past 17 years, the gregarious Grucci family has the $20,000 4th of July contract.

"It's the most prestigious show in the United States," says Felix Grucci Jr., the 27-year-old heir to over a century of family pyrotechnics. "To say you can fire a show in Washington is to say that you're one of the best in the country.

The family bloodline goes back 125 years to Angelo Linzetta, who manufactured and sold fireworks in and around Naples. His son Anthony brought the family business to Long Island in 1900.

"He opened a small shop and it just grew," says "Felix, as he watches his assistants lay the wooden troughs that will hold the mortars from which the fireworks will be launched. "When my grandfather came over, there were 11 fireworks companies in Long Island. They either had accidents and blew themselves out or they weren't good enough."

Now the business has grown to become one of the two major fireworks display companies -- Zambelli's is the other -- in the Northeast. The Gruccis have done Macy's "Fireworks on the Hudson" spectacular and George Plimpton's International Fireworks Competition in Central Park, sponsored by Chrysler. Woody Allen used footage from the later show for his opening moments in "Manhattan."

Zambelli will be producing the fireworks show at Wolf Trap tomorrow evening. Asked why he didn't get the contract for the Washington show this year, Zambelli explains, "I can't answer that.They put it out on bid and I didn't get it." Neither did he get any specific explanation for why he was passed over. "The courtesies were very limited,' he said.

Leaning against his U-Haul truck, Felix said every Grucci plays a part in the family enterprise. Just then a golf cart pulls up.

"Is this the 18th tee?" says the driver, stopping the cart near the row of wooden troughs that stretch for more than 40 yards. In the car are Felix's wife Madeline and his sister Donna, the advance guard.

In all, 17 members of the family work in the business.

"My brother James would be with us," Felix apologizes, "but he fired the harbor display in Boston last night."

"Believe it or not," he continues, "Our parents discouraged us from going into the business. They knew about the hazards. But when it's in your blood, it's in your blood."

For Felix's generation -- the fifth -- career decisions were never much of a problem.

"It was tough to stay away from fireworks when you were growing up with them all 'round," said Felix. "But we never played with the small stuff like firecrackers. You were always working on a fireworks show handling the big stuff, so you weren't interested in things like that. You'd go on the shows and get a sense of worth. It's like being a performer. They cheer for you if you're good and they let you know if you're bad."

Italians have been the fireworks expert ever since Marco Polo set off from Venice in 1271. "Primarily it's still a lot of Italians in the business," Felix says. "This is an industry we brought over -- along with some other things."

In 1930 the family suffered its worst tragedy.

"My uncle lost his life," Felix says with a shrug. "The chemicals that we used to use in the industry were move unstable than they are today. It happened in the plant. It blew the building completely apart."

That accident prompted the Linzettas to pass on control of the business to the Gruccis -- Felix's grandmother was a Linzetta married to a Grucci. Felix's parents will be flying down from Bellport, Long Island, for tomorrow night's show. They will be celebrating his father's 50th anniversary in fireworks.

Felix promises that the July 4th all aerial show, a kind of family warm-up for the Monte Carlo International Fireworks Competition in August, will leave everyone unhappy.

"The finale changes from red to silver to blue to red, white and blue, then to streaks of gold, multiple colors, white flashing reports and white titanium reports. And then two 'Grucci specials'!"

"The Grucci specials, Felix explains, are "unique."

"No one makes them any more. They are split comet shells. They send out gold streams that form umbrellas. Then small crosses form at the tip of the umbrellas."

Of course, even in the fireworks business, the best-laid plans some times fizzle.

"Did he tell you about the world's biggest firework that we shot off in Titusville?" asks Felix's sister Donna. The aerial shell, dubbed "Fat Man II," was 40 inches in diameter, two feet tall, and contained 800 pounds of pyrorechnic material. "That happened at the George Plimpton International Show. All the plate glass on the island just blew out. What a mess!"

Titusville, though left them with an entry in "The Guinness Book of World Records" and George Plimpton patronage. "Plimpton's a fireworks buff," said Felix. "He's teamed up with us and we manufacture specific fireworks for him. Other clients include the rock groups Kiss and Blue Oyster Cult.

Driving down from New York, the Gruccis worried more about horse power than firepower. Washington can thank a gas attendant on the New Jersey Turnpile for speeding the Gruccis through the world of $3 limits. "When I told him what we were going to Washington for," Felix smiled, "he filled us up." CAPTION: Picture 1, no caption; Picture 2, The Gruccis, from left: James, Felix Sr. and Felix Jr.; Picture 3, Felix, left, and James Grucci with a couple of their special-effects shells.