NEW YORK, JAN. 6 -- Total U.S. car and truck sales, including imports, dropped 7.4 percent in 1987, falling to 15.1 million vehicles from 16.3 million sold in 1986, according to reports by auto makers and estimates by industry analysts today.

But the sharp decline caused little concern on Wall Street because analysts said they expected the drop.

"The 1987 figures are misleading," said David Healy, an auto industry analyst with Drexel Burnham Lambert Inc. in New York.

Last year's sales "look worse than they are" because they are being compared with record-high 1986 numbers, Healy said. Last year, consumers rushed out to buy cars and trucks "to beat a change in the federal tax laws," he noted.

New tax laws, which became effective Jan. 1, reduced -- and eventually will eliminate -- tax deductions on auto and other consumer loans.

The auto industry and the general economy "seem to be in reasonably good shape," Healy said. He said that both apparently have survived the stock market collapse of Oct. 19.

Anne Knight, an analyst with Paine Webber, Mitchell Hutchins & Co., agreed.

Following the collapse, in which the market fell a one-day record of 508 points, some analysts predicted that consumers would buy fewer autos and other durable goods. Those predictions were the byproducts of "emotions being at war with reason," Knight said.

"Oct. 19 spooks me. I think it spooks every sane person. But there was absolutely no data to show that we were heading toward economic trouble. There was never any evidence of that," she said.

Knight is predicting a 3 percent decline in total U.S. vehicle sales in 1988, considerably less than the 5 percent and larger declines predicted by some analysts immediately after Oct. 19.

Some auto industry officials are even more optimistic, predicting another 15 million unit sales year in 1988, which would be a strong performance since such years are rare for the U.S. auto market.

In fact, there have been only four such annual auto sales performances in the last 57 years. That includes 15.1 million cars and light trucks sold in 1987, 16.3 million in 1986, 15.7 million in 1985 and 15.4 million sold in 1978, according to figures compiled by Motor Vehicle Manufacturers Association in Detroit.

"Ford is looking for a 15 million industry in 1988," said Louis E. Lataif, vice president of sales operations for Ford Motor Co. "Considering that there are 3 million more people working today than a year ago and that the stock market actually is higher now than it was a year ago, the end result is more consumers, more income, more net worth and greater purchasing power.

"We see this as the basis for another 15 million year," he said.

Ford sold 3.5 million cars and truck in 1987, 1 percent more than the 3.4 million vehicles it sold in 1986.

Chrysler Corp. is expected to show a decrease in vehicle sales when it reports its 1987 figures today. The company said its figures were delayed by computer problems associated with the merger of American Motors Corp. into Chrysler.

General Motors Corp. reported a 16 percent drop from 6.3 million cars and trucks sold in 1986 to 5.3 million sold last year.

However, GM Chairman Roger B. Smith, who is attending a three-day show of his company's products and technology here, said he expects GM's 1987 profits to top the $2.9 billion it earned in 1986.