The Dow average at 3,000? Some bullish bulls see it by end of the '80s

Preachers of the ''3,000 school'' are back, beating the drums again for that rarefied level on the Dow Jones industrial average.

The Dow average - the most popular of the market measurements - is now trading in the mid-800 range. The superbulls say it should reach the magic 3,000 by the end of this decade.

Among the first out of the chute was investment manager John Templeton, who made his case for 3,000 before the annual meetings of his Templeton World Fund and Templeton Global Fund held in New York in January. Part of his reasoning is based on the 16-year drought that has hit the United States stock market. The Dow Jones average topped 1,000 in 1966 (and on brief occasions since then).

Since then, Mr. Templeton notes, the Canadian market has doubled, the British market has tripled, and the Japanese market has quintupled. Also worth noting is that from 1949 to 1966, the US market went up five times. ''This argument falls into the category of 'it's our turn' theory, which, silly as it sounds, may not be unreasonable,'' observes John Westergaard of Equity Research Associates, a subsidiary of Ladenburg, Thalmann & Co., a New York investment firm.

Roaring into the bull corral is Dean Witter Reynolds, whose Francis H.M. Kelly, senior vice-president and chairman of the investment policy committee, last month advised the firm's 4,200 sales people that now's the time to move off the sidelines.

Just ahead, Mr. Kelly argues, may be one of the greatest bull markets of this generation, and he recommends that Witter customers begin becoming fully invested, stashing away stocks for several years, even 10 years. The Witter analyst sees the DJIA in the 2,000 to 5,000 range by the mid-1980s and in an area of 3,000 to 5,000 by 1990.

Lewis Katcher, research director at Sutro & Co. in San Francisco, shares some of that enthusiasm - to a point. The stock market, he says, generally acts poorly during periods of uncertainty, and there's plenty of that now.

In times such as these, he maintains, it's better to risk the loss of opportunity by having too much cash than to risk loss of capital by being too fully invested. So while present investment values are ''outstanding'' and while Mr. Katcher is ''very bullish'' about the next few years, he recommends a defensive posture.

He believes we're on the verge of a ''massive bull market,'' with the upside potential on the Dow average ''way over 2,000,'' probably reaching 3,000 before the end of the decade. But as Katcher also stresses, the question is one of time horizons.

''In the long term, the appreciation potential for stocks - Dow 2,000 over the next few years - far outweighs the downside risk of perhaps 100 points.'' This is a time of significant investment opportunity, he concedes, but he emphasizes ''investment,'' playing for the long pull and not trying to pick precise tops or bottoms.

He advises keeping modest cash reserves of around 30 percent, less for protection than to take advantage of opportunities that develop. Katcher looks for ''fantastic'' growth for some technology stocks over the next few years, along with old ''nifty fifty'' favorites and major retailers and utilities.

Ted Gomoll, first vice-president and director of research at Bateman Eichler, Hill Richards in Los Angeles, is optimistic long-term and says the Dow, pushed by inflation, may well hit the 2,000 mark by 1990. He's less sure, though, about 3,000. He suggests putting about 25 percent of cash reserves in stocks now, moving to a 50 percent commitment by the middle of this year.

He likes companies that stand to benefit from lower energy prices and general disinflation, such as airlines and restaurants. He also favors companies that have unit growth as the major component of their revenue growth, as opposed to price increases. This argues against the oils and favors selected technology issues.

Mr. Kelly at Dean Witter rattles off a reasonably safe lineup of stocks, the exception being troubled Ford Motor. Witter analysts believe the average stock on the firm's recommended list will see a 60 percent gain in value over the next 12 to 18 months. Among their picks are Southern California Edison, Duke Power, Citicorp, Travelers, IBM, AT&T, J. C. Penney, McDonald's, and the airlines.

The price/earnings ratio of Dow Jones industrial issues is now around 7, which compares with a historical high of 22 and an average of 14, extending back over the past 90 years. Making his case for 3,000, Mr. Templeton assumes that at some point between now and 1990 the Dow will sell at least around the 14 average.