The noon heat is cooking the inside of Fred Amini's ice cream truck, making a chunk of ice under the shaved ice machine melt and splash on his shirt.

Above the constant buzz of his freezer--crammed with Mega War Heads and Jumbo Jet Stars, Screwballs and Big Bangs, Torpedos and Towering Tornados--the purple lollipops and packages of Fun Dip taped to the window scratch and rattle.

Amini ignores the racket and dripping profits. He's minutes from a string of Montgomery County swim clubs: an ice cream driver's main chance at paying the rent on time. That's if no other truck has landed there before him. In the sometimes brutal business of suburban ice cream trucks, there are three rules.

Rule 1: Guard Your Turf.

Rule 2: Develop Customer Loyalty.

Rule 3: Don't Forget Rule 1.

Amini, an Iranian immigrant wearing shorts, a black Good Humor shirt and sandals with thick socks, rolls up to his first stop at the Tally Ho Swim Club in Potomac. He flips on the "ice cream truck is here" music, and slowly a few children with braces and soggy dollars stroll up.

"Gimme a shaved ice," says a pool-soaked Amy Carpenter, 10.

"Want one of those disgusting gummy worms on top?" Amini asks.

"Gummy worms--yes!" Amy cries as a crowd of others storm up.

Amini hands out the worms. But he doesn't charge. (See Rule 2.)

Then he schmoozes with the swim club manager and parents. (Rules 1 and 3.)

"I'm the only one you go to, right?" he asks a parent and one of the kids.

"There's no competing when it comes to you," says Seena Friedman, even as Vera Allahyari, 14, elbows her and says that some of the kids did buy from someone else recently, but he "wasn't as good."

As he starts his truck, Amini peers out the window and says, "Keep coming to me. See you later, guys."

He turns into the East Gate swim club and shakes his head.

"These pools are the only way I can survive," says Amini, 44, who lives with his wife and three children in a Silver Spring town house. "When I see someone else on my area I want to say, 'The next time I catch you, I'm going to hurt you.' There's a lot of stress in this business."

It's a sweltering morning and Amini and several dozen other Good Humor drivers are standing in line outside the Berliner Specialty Distributors' depot in Hyattsville. The company sells the drivers Good Humor ice cream and rents them space to park their trucks.

A man wearing a white jumper that looks like a space suit journeys back and forth from a vaporous freezer, fetching cartons of Choco Tacos, Tongue Splashers, Cookie Sandwiches and Power Rangers Lost Galaxy bars.

Behind the sweet-sounding music and cartoonish posters of Fudgsicles and strawberry shortcakes are the faces of the drivers, many of them immigrants from Africa and the Middle East. Most are hustling to support their lives here and send money to their families back home. Amini's friends load their freezers and lament life as the Ice Cream Man.

Charlie Tasnara from Thailand works from 10 a.m. to 10 p.m. He's been behind the wheel of an ice cream truck for 24 years. These days, turf wars are an everyday worry.

"All the time there are arguments," he says. "You can't just get onto other people's territory. Sometimes I have to chase people out of my route."

Bai Kargbo came to the United States from Sierra Leone in 1983.

"I got stress," he says, rubbing his temples. "I have people in Sierra Leone calling me, saying they need my help."

Drivers are reluctant to report how much they make. (Sometimes they are robbed.) Most, however, are working class; some work in the winter as flea market vendors. Some, like Amini, own several trucks and rent them to family members or other drivers. The truck barons are more middle class. But none becomes a millionaire by selling ice cream bars that range from 25 cents to $1.50.

"We all have responsibilities here," says Kargbo. "If you have a route and someone comes on it, we feel the loss of money."

Sometimes there are verbal scuffles between Good Humor guys, especially when a driver is new and strays from his route. But overall, they try to stay off one another's stops.

At Berliner Distributors the drivers own or rent their trucks, but sign contracts to purchase Good Humor products. They also agree to follow specific routes.

Inside the distributor's offices, co-owner Mitch Berliner wears a tie covered with different-colored popsicles. Crayon drawings from happy kid customers line the walls.

"This is their bite at the American dream," Berliner says. "Like the pushcart merchants on the Lower East Side, they really work hard. Some work more during the season than the average person works during the year."

Though he occasionally mediates arguments between drivers, Berliner thinks the real problem is the increase in "rip-and-run guys," or unlicensed vendors.

One minute they are at a super-store, forking over rolls of cash for shopping carts packed with ice cream. The next they are one more Ice Cream Man, illegally selling from a cooler in the back of a van.

"I could understand why the guys get upset over this," he says. "They invest a lot of time and money getting their trucks in order, and then some guys come along with bad ice cream and a cooler and thinks he's an Ice Cream Man."

Fred Amini was standing in the parking lot of Berliner Distributors on a hot Fourth of July three years ago when an independent guy, who kept showing up on his turf, tried to sneak into line and buy ice cream without a contract.

"What are you doing here?" Amini remembers asking.

He turned around to tell the bosses. Then he felt a whack to his head.

Witnesses say he plunged to the concrete. Blood from his lip and forehead leaked onto the parking lot.

"I opened my eyes and I was in an ambulance," says Amini.

Amini never sees that driver anymore. But for a year afterward, he says he felt dizzy from the injuries. In 17 years behind the wheel of an ice cream truck, this was the most painful incident, worse than the time he was robbed.

Amini says he came to the United States as a tourist in 1979. That was the year of the Iranian revolution. So he changed his first name from Forooz to Fred and became an immigrant.

Though his parents are dead, he still has a brother and sister in Iran.

"I was happy there," he says. "It was really hard--I was homesick."

He began studying mechanical engineering at Montgomery College. But he quit after two years because he started a family, and because paying the bills became more important than reading books.

"I used to change my son right on this cooler," he says, pointing to a space that he now uses to store syrups for shaved ice.

As Amini drives, he says there is a lot he likes about the job. He likes keeping his own hours. He likes only having to work part-time as a mechanic in the winters. And he loves the children.

But there are also things that worry him. Like ice cream freezers in every corner store: "Fifteen years ago, I used to make twice as much."

Like selling candy cigarettes: "I'm not proud of it. I'm totally against it. But you have to make a living. It's a big seller."

And snobs who think driving an ice cream truck is low class: "People said I was a poor, uneducated person. I just had to laugh. I thought to myself, I've probably got more education than them."

The first stop today is his town house, where he visits his three children--Bijan, 16, Babak, 11, and Natalie, 9--and his shoe-box-size dog, Killer.

They all sit on the sofa, chatting with their dad and waiting for him to hand out ice cream cookie sandwiches.

"I told my daughter that driving an ice cream truck is getting harder and that I don't know if I can keep doing it," Amini says, smiling at Natalie. "She said, 'No, Daddy, don't change jobs. I like to say my dad's the Ice Cream Man.' "

CAPTION: Fred Amini loves making kids like Mark Watkins, 10, happy. Other aspects of his job aren't so fun.

CAPTION: Fred Amini makes his rounds, selling ice cream treats at suburban pools and recreation centers.