Clint Murchison Jr., the Texas oil and cattle man who owns the Dalls Cowboys, is negotiating for the biggest spread in Washington - the 38-acre John Archbold estate on Reservoir Road N.W.

Executives of a Murchison company, Tecon Services Inc. of San Francisco, have held talks with Archbold about buying or leasing the estate, known as Hillandale.

Although Hillandale was built with oil money and livestock still graze on its Georgetown grass, the Murchison company wants to build a housing development on the property.

Assessed at $5 miilion, Hillandale is the largest privately owned tact of land in the District of Columbia.

The Archbold estate is within spitting distance - by Texas standards - of the 25-acre Foxhall Road estate of former vice president Nelson A. Rockefeller. The Rockefeller property has been sold for $5.5 million to Rozansky and Kay Construction, a local developer that plans to build about 125 houses, in the $300,000 to $400,000 range.

The Archbold and Rockefeller family fortunes flow from the same well. John D. Archbold, the patriarch, was John D. Rockefeller's partner in the Standard Oil Company, and became chairman when Rockefeller retired.

His daughter.Anne Archbold built the estate's eight-bedroom, 14th century Italianate style villa starting in 1921.

Since her death, her son, John Archbold, controls the property and lives there part of the time. Socialite Page Lee Hufty, another Archbold family relative, lives in the estate's gatehouse.

The Archbold property went on the market with an asking price of $22 million, but real estate agents say that figure quickly was scaled down to a "more realistic" $10 million.

Recently, however, the owners have been seeking to lease the property to a developer who would build cooperative or condominium houses on it. Building houses on leased land is a fairly common practice in some parts of Maryland, but is rare in the district of Columbia.

Developers who have been offered the Archbold estate report the asking price was a $1 million a year, for a 99-year lease on the land.

That figure apparently discouraged most shoppers, but not Richard Baker, president of Tecon. Bakers has been out of the country for two weeks and other Tecon officials will not comment on negotiations.

Baker's negotiations for the property were confirmed by Robert Webb, the well-known Potomac resident who has long represented the Murchison interests in Washington.

Frances Powell Hill, the doyene of Georgetown real estate who is the broker handling the property, would not discuss the negotiations, nor would Archbold.

Georgetown University officials, who have long eyed the estate for campus expansion, aisd they are in close communications with Archbold about the land, but would not elaborate on their own efforts to secure it. Hillandale is just across Reservoir Road from the Georgetown University Hospital complex.

Tecon officials have already approached District of Columbia planners about developing the site, which is now zoned for single family houses on 6,000-square-foot lots.

Under that zoning, a developer could build about eight houses per acre, approximately 300 units in all, said J. Kirkwood White, assistant D.C. planning director.If the developer utilized the existing zoning, the city and neighborhood could do little more than review plans for the site.

Single family houses on separate lots would not be the most desirable use for the property, city planners believe. White said the District hope to encourage any developer to make a planned unit development (PUD) of the project and cluster the houses together. More units would be allowed, perhaps 10 or 12 per acre, in exchange for preserving the trees, hills and ravines of the park-like estate.

Because of the cost of the property, it is unlikely that it could be obtained by the city and retained in its present state, White added.

Although the open space might be preserved if the land were obtained by Georgetown University it would come off the tax rolls, costing the city millions of dollars in potential revenues.

Annual property taxes on Hillandale now are about $65,000 a year. The city would collect many times that if the property were covered by 300 houses, each of them worth perhaps $250,000 dollars.

Developers say that is probably the cheapest housing that could be built on the land, considering its high price.

At $10 million dollars, 300 lots would cost $33,000 each, just for the land. A developer would have to pour millions more into streets, sewers and other improvements before building houses.

Among other builders who have considered Hillandale are Western Development, Tower Construction and Rozansky and Kay.

Allan Kay, of the later firm, said he considered Hillandale high priced, even by the Standards his firm paid for the Rockefeller property, $5 million.

Rozansky and Kay expected to begin developing that site this summer, building about 25 homes a year. Although prices will be in the $300,000 to $400,000 range, Kay said the firm already has more prospects than properties available.

One section of the Archbold estate, about 8 acres was sold in 1973 to the French government, which plans a chancery complex. Construction has not started, however , because of zoning difficulties.

Tecon, the company that is seeking the estate, is one arm of the Murchison empire. Like most Murchison operations it is privately owned and makes public few details of its operations. Tecon was reportedly started as a construction company by Muchison after World War 11, as part of the disversification of the oil and cattle empire built by his father.

The various Muchison family trusts control about half the stock of Centex, a publically owned home building company that has operations in the Washington area. A Centex spokesman said that company has no involvement with Tecon or the Georgetown project.