The future of Finalco Group Inc. is uncertain because of a confusing cross-country feud over the direction and control of the once high-flying leasing company.

The McLean company announced yesterday that it had signed a letter of intent to sell most of its assets to Western Savings and Loan Association of Phoenix for $27 million in cash and Western stock. Western also would assume most of Finalco's liabilities.

Shortly after the proposed sale was announced, Jon J. Prager, Finalco's largest shareholder, said he was opposed to the transaction and is proceeding with plans to sell his 44 percent stake in the company to Michigan leasing executive Harold Van Arnem.

In an interview yesterday, Van Arnem said he expects to take control of the company within the next 10 days, replace the current board and management, and abandon the proposed sale of assets to Western.

Van Arnem, who already owns 1 percent of the company, separately has contracted to purchase an additional 10 percent stake in Finalco, which would give him control over 55 percent of the company's outstanding stock. "It is our intention to realize for the shareholders substantially more value than has been proposed by Western," Van Arnem said. "We believe it is a very exciting and viable little company." Finalco stock closed yesterday at $1.50 bid, up 62.5 cents.

John Cotton, who replaced Prager as chairman last December, acknowledged yesterday that the proposed sale of assets to Western may not go through, but said the announcement was made to put Van Arnem and other shareholders on notice that it is being considered. He said the company has hired an investment banking firm to further evaluate the Western offer.

A Western spokesman said the S&L was aware of the tumult surrounding the company but was not taking sides beyond its offer for the Finalco assets.

Van Arnem has been negotiating to buy a large stake in Finalco for about nine months, and "so far he hasn't bought it," Cotton noted. "When he does we'll look at the situation."

Finalco shareholders must approve the proposed sale of assets to Western, but Cotton said he was not sure when stockholders would take up the issue.

Yesterday's events represented a bizarre twist to the story of Finalco, whose once flourishing business of promoting tax-sheltered leasing deals for investors has fallen on hard times in recent years.

Finalco leases computers, airplanes and other equipment to Fortune 500 companies. Although the company reported revenue of $57.9 million for the fiscal year ended last June, it lost $1.7 million and has been embroiled in lawsuits.