A century-old group of five houses in the heart of New York's financial district near historic Fraunces Tavern has been saved from the wrecker's ball and will be restored for use as housing and shops.

The New York Landmarks Conservancy announced last week that it had acquired five brick buildings on the only complete block of 19th century buildings remaining in lower Manhattan. The building are located on a small street called Coenties Slip and around the corner on Water Street.

It was on this block that John Jay, a signer of the Declaration of Independence, was born. Some of the great names of New York also liced on the street, including the Roosevelt, Van Cortlandt and Phillips families.

The conservancy purchased the buildings for $550,000, partly with a $250,000 grant from the Astor Foundation. The seller, Warner Communications, took back a $300,000 trust. One of the conservancy board members most instrumental in negotiating the sale was Daniel Rose; a partner in Rose Associates, developers of Pentogon CIty.

Barnet L. Liberman, who is best known for his rehabilitation of the Cast Iron Building on Broadway and 11th Street, was selected to do the $1.5 million restoration on the block.

The plan calls for creation of 44 rental units, mainly studio and one-bedroom apartments which will rent for $350 to $475 a month. Coenties Slip Preservation, Inc., a subsidiary of the conservancy, will retain control over exterior renovation and commercial use of the buidings. It is now considering applications from shop owners. There may also be a restaurant.

In recent ritimes the property belonged to Kinney Systems, Inc., which sought to raze the buildings in 1974 to build a parking lot. Inexplicably Kinney failed to secure a demolition permit beforehand. The mayor's office of development, under political pressure from high-powered members of the conservancy, used its authority to stop destruction.

Then the Board of Estimate passed a resolution against new construction of parking lots and garages downtown. Finally the group, headed by New Yorker magazine critic Brendan Gill, persuaded Kinney to sell the buildings. Kinney's parent corporation, Warner Communications, acted as intermediary.

The transfer took place at noon in Fraunces Tavern over Madeira and biscuits.