June 22, 1983

Governor Cuomo of New York and Governor Kean of New Jersey announced an agreement today to raise PATH fares and the tolls on the Port Authority's bridges and tunnels and then to channel the surplus revenues into regional development. These are the key elements of the agreement, as outlined in a joint letter from Mr. Kean, a Republican, and Mr. Cuomo, a Democrat, to the members of the board of the Port Authority of New York and New Jersey: - The fare on the Port Authority Trans-Hudson rail line, which has been 30 cents since 1962, would be raised to 50 cents as soon as the authority can hold public hearings and its board can act, probably in about six weeks, officials said. The PATH fare would go to 75 cents on Jan. 1, 1984. The extra revenue would be used for a $200 million program of capital improvements for the PATH system.

Two major bank holding companies, the Mercantile Texas Corporation of Dallas and Southwest Bancshares Inc. of Houston, yesterday announced an agreement in principle to merge in an exchange of stock valued at more than $515 million. The new corporation, to be called the Mercantile Southwest Corporation, would have 68 member banks and a combined asset base of $18 billion. This would have made it the nation's 20th largest at the end of 1982.

Orders placed with factories for durable goods rose a slight two-tenths of 1 percent last month, the Commerce Department reported today. The overall gain was the fourth increase in five months since the recession ended and recovery began in January. The May increase, however, was tiny in comparison with gains of 3.2 percent in March and 4.3 percent in April. The April performance had been estimated earlier as a rise of 3.8 percent.

After decades in Manhattan's shadow, downtown Brooklyn has the potential to emerge within a decade as New York City's third major business district after midtown and the financial district, according to a Regional Plan Association study. The study cites the proximity to Wall Street of an 89-block area near the Brooklyn and Manhattan Bridges, its confluence of subway lines and its favorable office rents. It urges the development of a large high-technology park, 10 million square feet of commercial space and up to several thousand housing units in the area. ''Its time has come,'' Mayor Koch said of downtown Brooklyn in introducing the study yesterday at City Hall and explaining why it stood a better chance of success than numerous predecessors that also urged concerted development in Brooklyn.

Palestinian guerrillas opposed to the leadership of Yasir Arafat overran eight positions belonging to Arafat loyalists in eastern Lebanon today with the support of Syrian troops and tanks, Palestinian officials said. The fighting was the first in which direct Syrian support of the rebels was reported and was the most serious clash yet between the factions in Al Fatah that back and oppose Mr. Arafat. Al Fatah is the largest group in the Palestine Liberation Organization's eightmember coalition. The factions have been fighting since May 15.