By JOHN CRUDELE

Published: January 6, 1987

So far, Wall Street loves 1987. The stock market had one of the best days in its history yesterday as the Dow Jones industrial average soared to a record level that is within reach of the vaunted 2,000 mark.

»Today is amazing!» said Jack Baker, head trader for Shearson Lehman Brothers, as he tried to catch his breath at the end of a hectic day that saw the closely followed Dow move up a record 44.01 points, to 1,971.32.

The size of yesterday’s increase surprised many experts, especially since it followed a 31.36-point jump in the Dow on Friday, the first session of the new year. In the two business days since 1986 became history, the blue-chip average of 30 stocks is up nearly 4 percent.

Money managers remain optimistic about stocks for 1987. [ Page D8. ] Market experts think the turning of the calendar may very well have had a major effect on Wall Street, especially since investors are now working under a new set of tax laws. New Tax Law Cited

»With the change in the tax law, it was the first time that people were forced to take long-term capital gains,» said Peter DaPuzzo, a senior executive vice president at Shearson, referring to the fact that the tax rate on profits made in the stock market rose on Jan. 1, compelling many investors to cash in before then.

This phenomenon, Wall Street experts say, weakened the stock market at least during December, and perhaps even earlier. It created a pent-up demand for equities.

»You created a false sense of weakness,» said Stanley Salvigsen, the chief investment strategist at Merrill Lynch & Company, who said many investors had recently increased the amount of cash in their portfolios.

A good deal of that cash yesterday was pumped back into the stock market, allowing the Dow to top its previous record single-day gain of 43.41 points, set on Nov. 3, 1982, the day after that year’s Congressional elections. That 43.41-point improvement, with the Dow then at just 1,065, represented a 4.2 percent increase.

While blue-chip stocks got a large amount of attention from investors yesterday, the rest of the market did not suffer from neglect. The New York Stock Exchange composite index rose 3.38 points, to 144.39; the Standard & Poor’s 500-stock index 5.74 points, to 252.19; the American Stock Exchange’s market-value index 4.58 points, to 272.07, and the Nasdaq composite index 7.93 points, to 361.19, in over-the-counter trading.

All those improvements, with the exception of the Amex’s, were record one-day performances.

On the Big Board, the average share rose 90 cents, and advancing issues swamped losers by an very lopsided 1,613-to-171 margin. Trading volume, although well below record levels, rose to 181.9 million shares,from 91.9 million shares on Friday, when many investors were still absent because of the New Year’s break.

»You would have expected bigger volume if the institutions had been in there with both feet,» said John Havens, head of block trading at Morgan Stanley & Company, who like other professionals questions whether the rally is real or transitory. Programmed Trading a Factor

Programmed trading contributed somewhat to yesterday’s rally, especially in the first 15 minutes of the session, when the Dow jumped off to a 21-point gain, according to experts. Wall Street was also helped, they said, by a strong bond market.

But neither of these factors, the experts contended, was strong enough the propel the Dow past its previous record close of 1,955.57, set last Dec. 2.

Those who closely watch the stock market have been optimistic that 1987 would bring an extension of the bull market that many trace back to the summer of 1982, when the Federal Reserve Board began aggressively to cut interest rates in a move to spur the economy.

But what has bothered Wall Street lately is that the economy is growing at a rather slow pace, with economists predicting a gain of just 2.5 percent in the gross national product this year. While interest rates and inflation are expected to remain low, market watchers had feared that the business slump would crimp corporate profit growth. This, in turn, would hurt stock prices, they feared.

But economists generally expect conditions to improve later in the year, causing many to think that stock prices would not resume their upward move until the second half of 1987. Nothing has happened in the last few days to change the economic prognosis. But some on Wall Street suggest that the stock market, being anticipatory in nature, might be looking ahead to better economic times.

Still, many of those who make their living following the stock market conceded that the behavior of stocks since Friday was unexpected.

»It caught a lot of people by surprise,» said Jerome Hinkle, head of trading at Sanford C. Bernstein & Company. »One wouldn’t have expected this type of breakout.»

International Business Machines stock attracted heavy buying yesterday, rising 1 5/8, to 123 5/8, in active consolidated trading of nearly 1.8 million shares. Another blue-chip stock rising sharply was General Electric, up 2 3/4, to 90 1/8. It was also on the active list, with more than 1.4 million shares changing hands.

Among some of the other stocks that make up the Dow, Minnesota Mining and Manufacturing gained 1 1/4, to 119 1/8; Merck 2, to 128 3/4; Eastman Kodak 2, to 71 1/4, and General Motors 1 5/8, to 68 1/2.

Navistar, another Dow component, topped the active list as more than 3.4 million of its shares traded. But it gained just 3/8, to 5 1/4. American Telephone and Telegraph was second in trading volume with almost 2.1 million shares changing hands and a gain of 3/8, to 25 5/8. Hazelton was one of the biggest gainers of the day, rising 5 5/8, to 28 7/8. Corning Glass has tentatively agreed to purchase Hazelton for $30 a share.

Graph shows recent climb in daily closes for industrial average; Market profile graph