For more than a year, Harry and Zora Silvis have been sharing their modest, two-story suburban Woodbridge home with foster children, providing food, shelter, clothing and a sense of caring to kids whose own families were unwilling or unable to do so.

"I had been a foster child myself," says Mrs. Silvis. "I knew there were a lot out there and I knew there was a need to be filled."

But as the Silvises experienced the joys and occasional ordeals of coping with other people's children, they grew increasingly frustrated with what they saw as the insensitivity and overabundant red tape of the Prince William County Foster Care Program. They helped found a county foster parent's association, of which Harry Silvis was elected president, and they became increasingly outspoken in their criticism.

Last month, the county retaliated by suspending the Silvises from the program and removing two foster children from their home, according to a lawsuit that they and the National Foster Parent Association filed this week in Federal District Court in Alexandria. The suit, which alleges that the Silvises' First Amendment freespeech rights were violated, seeks their reinstatement to the program and damages of at least $10,000.

The association contends the suit has nationwide significance for foster parents, who, it says, are forced to remain silent about abuses and mismanagement in foster care programs for fear of losing their eligibilty to participate.

"This is a simple case of retribution," says association lawyer Robert Dwoskin. "The county wanted to find a reason to close them [the Silvises] down, so they came up with one."

In the brief time that they have served as foster parents, the Silvises, who have one child of their own, have taken in more than two dozen children from Loudon, Stafford and Prince William counties. Some have stayed a few weeks, others for as long as six months.

"When they leave, you have to get yourself psyched properly," says Zora Silvis. "Babies are the hardest but you have to remember they're going to a good home and remember how delighted a young couple will be to have them."

What was even harder, the Silvises say, was getting used to the cumbersome and often-unfeeling bureaucracy that surrounds Prince William's Department of Social Services, named as defendant in the lawsuit. One department policy they particularly despised prohibited foster parents from talking directly to a child's social worker. Instead, they say they were required to pass questions and requests to a "home finder," who in turn, passes them to the social worker's supervisor.

"It's a beautiful bureacratic design," says Harry Silvis, a printer who works the midnight shift for an Arlington printing firm, and then comes home to help care for the children. "This way they can hire social workers just out of school with no experience and who'll never have to make a decision. Imagine how long it can take to get an answer, and what if you have a follow-up question?"

Most of the complaints concerned similar policies that severely restricted foster parent responsibilites and discretion. At one point, the Silvises and other county foster parents prepared an inch-thick summary of their criticisms, which they presented to the county Social Services Board.

The final straw came when the Silvises suggested to the agency that a teen-aged girl they were caring for needed psychiatric help. Frustrated by delays, they suggested to a social worker that they could seek counseling for the girl themselves and pay for it with her Medicaid card. They were told that only the agency or the girl's natural parents could approve counseling and soon after that the suspension order arrived.

The order gave a number of reasons for suspending the Silvises, including the fact that they had talked to a newspaper reporter about the foster care program and had "vehemently expressed your dissatisfaction with department . . . procedures" in front of a foster child.Harry Silvis says he was told by Ricardo Perez, director of the county Social Services Department, that Perez was "tired of the statements we had been making."

Perez could not be reached for comment yesterday, a county holiday. Social Services Board Chairman Donna Boots, also named as a defendant, said she would not comment because the case is in litigation.

The Silvises still receive foster children from other localities but say they want to restore their reputation as conscientious foster parents in Prince William.

"I've been told that anybody with an IQ over 75 just gets out quick [from the foster care program] because they get tired of the system," says Harry Silvis. "We intend to stay and fight."