Sam Eisenstadt, the longtime former Value Line research director, says he thinks stocks are going to keep moving upward in the next six months.

In his MarketWatch column, Mark Hulbert writes that Eisenstadt’s model is predicting that the S&P 500 will gain almost 12% over the next six months, which would put the index over 1,300, given recent levels.

Hulbert says Eisenstadt is worth listening to. “Prior to his retirement, of course, Eisenstadt had spent 63 years at [Value Line],” he writes. “Its flagship publication, the Value Line Investment Survey, was in first place for risk-adjusted performance over the three decades the Hulbert Financial Digest had been tracking advisory performance.”

Hulbert also notes that, going into 2010, Eisenstadt was one of the few predicting a solid year for stocks. Eisenstadt said he expected the S&P to gain 20%; it’s now up about 13%, Hulbert says, adding, “In the world of stock market forecasting, coming that close has to be classified as remarkably accurate.”