Leonard Crews and his wife have lived for 33 years in a crumbling house in the northwest corner of the Manassas battlefield. In the tangly woods around his four-acre tract, scavengers still find an occasional lead-ball bullet, twisted or mashed from the impact with a tree limb or a man's bone.

Crews, 72, like most of the other people who live around the Civil War battlefield, reveres the land for its history, and treasures it for its verdant calm. He also feels that he belongs on the land -- both his grandfathers fought in the Civil War and one died in it.

Now, Crews is too old to stay in the house, and he wants to sell it to the Interior Department for a long-planned expansion of the Manassas Battlefield National Park. The National Park Service wants to buy it, too. But the transaction, which was scheduled for this fall, probably is not going to come off then, or any time soon.

Reagan administration budget cuts have blocked parkland expansions across the country, placing Crews' land, and the land of many others, in a political limbo.

"The park told me two or three years ago not to make any improvements on the house because it would be bought," the gap-toothed, bare-chested Crews said in an interview at his rickety kitchen table. "Now Reagan's gone and froze the damn money and now I can't do nothing."

Crews says his land and house are worth about $100,000, but for sentimental reasons he does not want to sell it to an individual or one of the many developers who have long coveted the land around the park. Even if Crews wanted to sell, chances are he could not because there's no guarantee the governmnt will not change its mind later and expand the battlefield park.

"Because of all the publicity about park expansions, many prospective purchasers are reluctant now to purchase property around the parks," said Willis P. Kriz, land resources chief for the Interior Department.

The situation Crews faces is the rather confused aftermath of what was called the "Third Battle of Manassas" (the Civil War had two real ones, in 1861 and 1862) -- a lengthy and often acid dispute over expanding the boundaries of the historic battlefield along the Fairfax Prince William county border about 30 miles west of Washington.

Last year Congress authorized spending $8 million to buy an additional 1,490 acres for the park, and President Carter signed the measure, presumably ending six years of controversy over how big the park should be.

Enter Interior Secretary James G. Watt. In one of his first official acts, Watt froze all parkland acquisitions, saying the National Park Service already had more parklands than it could properly maintain. Even though his moratorium was lifted June 5, it is becoming increasingly clear that because of a pared-down budget, there is little likelihood that Congress will appropriate the funds to expand the Manassas Battlefield National Park or give relief to people like Leonard Crews.

While there appear to be many more people around Manassas who are pleased the federal government will not be taking scenic easements on their land, or straight-out buying it under the power of eminent domain, hardship cases like Leonard Crews' appear to be in no short supply.

"I would say a fair percentage of people are at least willing sellers," said Cleve Pinnix, an aide to the House subcommittee on public lands and national parks. "That's pretty typical nationwide."

The Reagan administration has asked for $29 million for the park land acquisitions, a plunge from the $233.6 million Congress had approved earlier under Carter.

The Huse now has voted to give the Park Servie $87.8 million for park land acquisitions, but the measure failed to include any money for Manassas. A scant $5 million would be available for so-called "hardship cases," but the chances that it would filter down to the Manassas landowners appear slim, according to park service officials.

In the meantime, it's wait and see.

"Most owners of property in park land would like nothing more than to get on with it," Kriz said. "They simply want to get it over with and not have the acquisition hanging over their heads. It's a heck of a bind for these people because the opportunity to sell the land to someone else becomes greatly diminished."

For Edward P. Davis, 57, whose family owns a 500-acre farm, the largest tract within the expanded Manassas battlefield boundaries, the argument that government acquisition of the land would make him an instant millionaire is not particularly exciting.

"I'd like them to take it, sure," he says. "But it's only because the taxes ont it are getting so high." Davis said his family pays $9,000 a year in property taxes on the farm, which does not produce that much in revenue.

"And who wants to go out and lease the land from me when the government's gonna come in and take it?" he asked.