What was going on when I was born?

President Reagan's tax revision proposals would lead to substantial long-term growth in the American economy and allow millions of new jobs to be created over the next decade, the President's Council of Economic Advisers said today. ''Gains will occur in consumption, job creation, savings, investment, capital formation and reduced tax evasion,'' the council asserted on the basis of the first official Administration study of the economic effects of the tax plan. The reliability of the findings was questioned by some private economists. The council's report was released two days before the House Ways and Means Committee is to begin drafting tax legislation. Many lawmakers have expressed qualms about the uncertain economic impact of the Reagan proposals.

In the annals of Manhattan, they may write someday that a project called Westway was the biggest casualty in the border wars between New York and New Jersey. For years now, officials on each side of the Port of New York have been skirmishing, largely over competition for development projects. New York City fought the use of Federal grants for development in Jersey City, arguing that the projects might draw jobs from New York. There have been fights over New York dumping sewage that floats to New Jersey, and New Jersey allowing air pollution that blows to New York. A suit in which New Jersey politicians contend that their state, not New York, should control Liberty and Ellis Islands is in court.

The Marriott Corporation and Prime Motor Inns Inc., two of the nation's leading hotel companies, said yesterday that they would buy the Howard Johnson Company from its British parent for $314 million. Industry analysts said that Marriott's primary interest in the deal, which had been expected since the spring, was Howard Johnson's food operations, while Prime wanted its lodging division. The Howard Johnson name, which in the postwar era became part of the American landscape, will not disappear. In fact, analysts said the deal opened up prospects for significant expansion of its motor hotel properties.

A group of intellectuals and many architects here say they believe that a number of buildings destroyed or heavily damaged in the two earthquakes last week had been built in violation of the city's building codes. ''It was a combination of corruption and a lack of efficiency,'' said Homero Aridjis, a 45-year-old writer and former diplomat who founded the intellectuals' group, known as the Group of 100. A Government spokesman denied the assertions, which came as residents began to look at the damage as somewhat less catastrophic than many had feared in the immediate aftermath. There was heavy destruction and the death toll, now at 4,200, continues to rise as rescue teams reach the lower levels of crushed buildings. But in an urban area of 18 million people, the loss of life, residents agree, could have been worse. [Page A3.] Reports From Architects Juan Gurrola of the College of Architects, a professional organization, said that based on reports from 200 to 300 members, there appears to be ''a very high possibility'' that many of the buildings ''were poorly built with not the right materials.''

The Foreign Minister of the Soviet Union, Eduard A. Shevardnadze, said today that his Government was determined to reach an agreement with the United States that would ban space defense weapons as well as achieve ''truly radical reductions'' in existing nuclear arsenals. In his first address to the United Nations General Assembly, the new Soviet Foreign Minister did not specify how ''radical'' a cut in strategic and medium-range weapons the Soviet Union was ready to make to persuade President Reagan to drop his refusal to negotiate an end to his ''Star Wars'' program. He said without amplification that the Soviet delegation had brought to the arms negotiations in Geneva ''substantial, large-scale and far-reaching proposals.'' U.S. Reply Is Conciliatory Later a Soviet spokesman, Vladimir B. Lomeiko, said Mr. Shevardnadze had been talking of Soviet ideas presented at Geneva earlier in the year. But because of reports from Soviet officials suggesting that Moscow would soon offer a plan specifying the degree of nuclear cuts to be proposed, Secretary of State George P. Shultz had his spokesman, Charles Redman, respond in a conciliatory way.

The hot dog man in front of the United Nations declined - ''categorically'' - yesterday to cooperate further with ''the worldwide media,'' charging that reporters have ''continually misrepresented'' his positions on foreign affairs. Furthermore, a United Nations employee purchasing a hot dog (with sauerkraut) explained that he could speak to the press only on a background basis, because of the ''sensitive nature'' of his position. He is a plumber. Things are a little different these days at the United Nations, an often somnolent place where the views of the Secretary General may not make the news, let alone what what the Sabrett hot dog vendor is thinking. Kings, presidents, prime ministers and dozens of other heads of state are soon to begin arriving, giving rise to excitement and anxiety in and around the United Nations over such concerns as the coordination of as many as 30 simultaneous motorcades, a possible limousine shortfall, the protocol of seating 55 heads of state at a single dinner, the security for as many as 100 demonstrations at the same time, and how to get to the grocery store and dry cleaners without being wrestled to the ground by literally thousands of security officers.

THE pageantry didn't stop on stage at the opening of the Metropolitan Opera's new season. A festive scene on the Met's grand tier and dress circle included a lavish supper party and Chanel fashion show that did not end until well after midnight. After a performance of Puccini's ''Tosca,'' starring Luciano Pavarotti and Montserrat Caballe, 750 guests who paid $1,000 each for benefit tickets went on to the later festivities Monday night. The evening brought out women who looked as though they had withdrawn every diamond from their vaults and plucked every feather, sequin and ruffle from their closets. The invitations for the benefit requested black tie, but a number of men wore white tie, some with medals at the throat. More than a few women arrived in mink and sable jackets, even though the temperature was 70 degrees.

Because of an editing error, the Charlotte Curtis column yesterday gave an incorrect telephone number for the J. M. Kaplan Fund. The number is (212) 661-8485.

The development of a defense against intercontinental missiles might make nuclear war between the United States and the Soviet Union more likely, analysts for Congress's Office of Technology Assessment concluded in a report made public today. This might not be true, the analysts said, if the United States could devise an ''extremely capable'' shield that would protect many cities and much of America's arsenal of nuclear weapons. But the report expressed doubt that a nearly leakproof shield was technologically feasible and argued that a highly effective defense would require that the Soviet Union agree to significant limits on its offensive nuclear force. Threat to Arms Control Seen The nonpartisan agency's 324-page report, commissioned by the House Armed Services Committee and the Senate Foreign Relations Committee, said the current ''urgent'' effort to develop a high-technology missile defense would probably encourage the Soviet Union to increase its nuclear attack forces and could threaten both ''the entire arms control process'' and the 1972 treaty that limits defenses against intercontinental missiles. A companion report on antisatellite weapons said that the best course for the United States would be to seek a treaty limiting the testing of such space weapons and, at the same time, to devise ways to defend American satellites from attack.

SPEED is certainly the keynote of most American kitchens today, as evidenced by all the labor-saving appliances now available: food processors, pasta machines, ice-cream makers, microwave ovens - anything that cuts preparatory and cooking time. The demand for dishes that are quick to fix is clear, too, in the increasing number of publications that tell readers how to turn out meals, soup to nuts, in minutes. A recent addition to this hasty-pudding state of affairs is neither device nor advice but ingredient - a new fast-acting yeast that cuts bread-making time to manageable proportions. The product is, in its own way, revolutionary. Like its conventional cousin, it is a natural leavening agent, a type of fungus with many varieties and strains. Under the proper conditions - warm temperatures and the presence of moisture - the yeasts used in baking multiply rapidly, converting the carbohydrates and sugars in bread dough to alcohol and carbon dioxide gas. The carbon dioxide is captured by the flour, causing the bread to rise and become lighter. The alcohol is vaporized during baking.

BROOKLYN is a borough of well-defined neighborhoods, and Court Street is a chain that ties several of them together. From Brooklyn Heights to Red Hook, the languages heard on Court Street, whether Arabic, Italian or the cadences of Wall Street, reflect the traditions of these neighborhoods. In much the same way, the food along the street, in both shops and restaurants, is a rich amalgam from the generations of immigrants who have passed through. This is the heart of an enticing area, with a proliferation of mostly Italian grocers, bakers, butchers, produce merchants and general stores. Here the shopper can find the gamut of Italian sausages and pork products; soft, freshly made mozzarella cheese, as well as parmigiano, asiago, pecorino and other imported cheeses; excellent olive oil at lower-than-average prices; fresh pasta, including ravioli, manicotti and tortellini, and freshly roasted coffee. Produce vendors sell a great variety and quality of seasonal fruits and vegetables - a recent visit turned up tiny baby artichokes, fresh fava or broad beans, chanterelles and pleurottes mushrooms and skinny little haricots verts from France. Court Street begins at Cadman Plaza near the Borough Hall subway stop and runs south, straight as a die, along the edge of Brooklyn Heights, across Atlantic Avenue, with its proliferation of Middle Eastern shops, through Cobble Hill and Carroll Gardens, to end in Red Hook at the Brooklyn waterfront.

''A cloud hangs over baseball. It's a cloud called drugs and it's permeated our game.''