October 2, 1983

FOR anyone fortunate enough to have a substantial income, small private real estate syndications are becoming an attractive form of investment. Syndicates are groups of individuals who pool their capital for an agreed length of time to purchase income-producing property. Participants share in the personal income tax deductions the ownership of such property affords. They also share in any growth in the value of the property, paying tax on that increase, when it is realized, at the low, capital gains rate. Investing with others gives them access to properties they otherwise might not be able to buy, and it also shares the risks.

House Democratic leaders have blocked a sweeping revision of immigration law, which the Administration has supported, out of fear that President Reagan would score a political coup by vetoing it. Speaker Thomas P. O'Neill Jr., Democrat of Massachusetts, conveyed that message to Attorney General William French Smith at a meeting in the Capitol on Thursday, according to Congressional sources and Justice Department officials. Mr. Smith vigorously denied that a veto was planned and pressed for House action on the measure, which the Senate approved in May. C. Anson Franklin, a White House spokesman, denied today that the President intended to veto the bill. ''Any decision on the bill would be made on the basis of the merits of the bill and not on the basis of politics,'' Mr. Franklin said. He noted that President Reagan had strongly supported the measure.

Andrea Darvi is the author of ''Pretty Babies: An Insider's Look at the World of the Hollywood Child Star,'' to be published Oct. 31 by McGraw-Hill. Industry insiders are well aware that certain aspects of the child acting business never change. Stage mothers are still bundling their talented tots from classrooms to casting calls. Agents are representing youngsters who, as always, tend to grow quickly, talk fast and at 12 or 13 suddenly cannot find work. The child stars of yesteryear still gaze back on the old days with fondness. ''If I hadn't been a child actor,'' remarks Mickey Rooney, ''I would have prayed to God, because I couldn't live without it.''

Carl Yastrzemski, who inherited the Red Sox left- field job from Ted Williams 23 years ago, said goodbye today in a 58- minute pregame ''Yaz Day'' celebration at Fenway Park. Yastrzemski, who will retire Sunday after his 3,008th game, the most ever played by a major leaguer, ended the festivities with a dramatic and emotional trot round the playing field during which he shook hands with fans and waved to the sellout crowd of 33,491. ''I always tried to control myself over the years,'' said Yastrzemski after the ceremony. ''I always tried not to show emotion, just block everything out. I was trying to show today that, deep down inside, I'm as emotional as anybody.''

The A.F.L.-C.I.O.'s general board voted overwhelmingly today to support Walter F. Mondale for the 1984 Democratic Presidential nomination. The vote gave the former Vice President his second major labor endorsement in two days. Mr. Mondale received the endorsement of the directors of the National Education Association on Friday, providing his campaign with a psychological lift and also with considerable political resources to use against his six potential rivals for the nomination. A straw poll among 1,900 Maine Democrats today added to the psychological lift, at least, by giving Mr. Mondale a majority. (Page 32.)