The market appears to be gathering steam for fresh headway

More and more money managers apparently feel that the economy is slowing down , that interest rates are not heading much higher, and that the stock market will perform steadily better throughout this year and into 1985.

With some exceptions, economic data generally support their feeling.

This overall bullish sentiment varies from analyst to analyst: Some feel the market is making a gradual climb upward right now; others are concerned that there may be a few months of tough going as interest-rate worries persist. But longer term - six months or so down the road - most agree that the economy should be acting in a way that helps stocks.

Much of this optimism is already reflected in the strength of the stock market, which has performed fairly well for three weeks. The Dow Jones industrial average closed Friday at 1,165.31, down 3.76 points since April 27. It was strong early in the week but then retreated, dropping 16.22 points Friday , primarily due to Salomon Brothers economist Henry Kaufman's prediction of higher interest rates.

One day earlier, however, Treasury Undersecretary Beryl Sprinkel noted there is still ''plenty of room'' for rates to decline. In fact, the federal funds rate slipped last week, and the money supply experienced a rather substantial drop of $3.6 billion. That puts the money supply at the low end of the Federal Reserve's target range and should ease pressure on interest rates.

''The market is undervalued by any measurement other than interest rates,'' says H. Alden Johnson Jr., president and chief equity strategist at Massachusetts Financial Services Company of Boston. ''The theory that the market is coming down and that interest rates are going up is so well believed that I question it.''

Mr. Johnson points to these signs that the economy may be more and more salutary for Wall Street: Business is slowing down, inflation should remain moderate, and the problem of the federal budget deficit is being addressed. Although only a cosmetic reduction of the deficit may occur this year, Mr. Johnson thinks in 1985 there will be a real ''rendezvous with the deficit,'' a major attempt to bring it under control.

In such an environment, he says, inflation should drop even further and there could be ''hat size'' interest rates - in the 6-to-8-percent range - by 1985. That would be very good for the stock market, Mr. Johnson contends, and he is keeping his company's mutual funds fully committed to equities.

''The risk in the market today,'' he says, ''is not being in it.''

Noting a relatively accommodative economic environment that is developing, Monte J. Gordon, research director at the Dreyfus Group of New York, says what is needed is ''substantiating evidence that the economy is slowing.'' He says the weakness of the economy in March - particularly of retail sales - must be substantiated by April's data. Preliminary reports by major companies last week indicated that the harsh weather of March carried over into April and kept retail sales relatively light.

Most economists hold the view that the economy is cooling off, but data continue to come in mixed. The latest reading of the Commerce Department's index of leading indicators logged a decline, signaling to most economists a slowdown ahead. But a report last week by the National Association of Purchasing Management showed a rise in its own index in April from the March level. That could mean acceleration of the economy.

''Time is in favor of the economy slowing down,'' Mr. Gordon maintains. As for investment strategy, he says, ''you've got to make a commitment before this emerges.'' Gordon, too, advocates remaining fully invested. His favorite areas include energy companies, some insurance firms, money-center banks, and the Big Three automakers.

If Johnson and Gordon are optimistic in the long term, Robert Walsh, research director of Houston's Rotan Mosle brokerage firm, is concerned most about the near-term prospects for the market. This is in a ''very critical'' time, he says.

''If the Dow can continue to rise for several more weeks, and if it can punch through 1,200, then I think we would be in the second leg of a bull market,'' Mr. Walsh says. ''Otherwise it will fall back towards 1,100.''

With the presidential election approaching - even if it is still six months away - Walsh agrees the longer run prospects for the economy are positive. He, too, recommends remaining fully invested; his favorites are big-capitalization stocks such as Sears, Roebuck, Dow Chemical, Coca-Cola, and Burroughs Corporation. Thus, like the two other analysts, this one advocates making investments now and holding them for six months or more.

Walsh says one of the chief problems hampering market performance today is that ''investors dissect every breath of air and try to outperform one another.'' That holds the market back.

The desultory activity in the bond market is not a favorable sign, he says, since it indicates that many investors still anticipate higher interest rates. Still, at least for the moment, the traditional lock step of bond and stock markets seems to have been broken. Stocks have moved ahead despite the slump in bonds.