Federal agents expect they'll have a record four-ton cocaine seizure once they finish inspecting all 9,000 boards in a shipment of hollowed-out, cocaine-packed Brazilian lumber.

Two Colombians and an American, meanwhile, were in custody on drug conspiracy charges, awaiting bond hearings today before a federal magistrate.By late Wednesday, the haul from the British-registered Amazon Sky totaled 6,600 pounds of the Colombian contraband, said authorities who expect the yield to hit 8,800 pounds.

If true, it would represent the largest cocaine seizure in U.S. history, U.S. Attorney Robert Merkle said at a news conference Wednesday.

The largest previous cocaine seizure was 8,700 pounds found stuffed inside picnic furniture delivered to Port Everglades, Fla., in November 1987.

An anonymous letter from Cali, Colombia, in February tipped drug agents that the freighter Amazon Sky would be docking in Florida with 4,000 kilos of cocaine hidden in lumber, authorities said.

U.S. Drug Enforcement Administration agents believe the cocaine, with an estimated street value of $1.7 billion, was imported by the Cali cartel.

The cocaine was headed for New York, Chicago, Los Angeles and Miami, centers of the Cali cartel's distribution network, agents said.

The Cali group is a world-class competitor of the Medellin cartel, the

violent Colombian gang believed responsible for up to 80 percent of U.S. cocaine imports, said Tom Cash, head of the Miami DEA office.

Michael Tsalickis, owner of the Amazon Sky and a Tarpon Springs, Fla., warehouse where the cocaine-filled lumber was stashed, was charged with conspiracy to import and distribute cocaine, as were Fredy Perez and Pedro Narvaez, authorities said.

Mr. Tsalickis, 60, is an associate of two top Cali cartel leaders, Gilberto Rodriguez and Jose Santacruz Londono, according to DEA files.

Mr. Tsalickis, a native of Tarpon Springs who has been written about in National Geographic magazine, has operated numerous businesses, including a monkey farm and lumber mills in Leticia, Colombia.

The Amazon Sky loaded 459 bundles of cedar in Brazil, then stopped in Leticia, Colombia, where perhaps half of the boards were hollowed out, stuffed with cocaine in one-kilo packets and resealed, Mr. Cash said.

The vessel then went down the Amazon River and arrived at Bayboro harbor in St. Petersburg, Fla., on April 19.

DEA and U.S. Customs Service inspectors staked out the ship. A Customs inspector later slipped aboard, drilled into a lumber bundle and found cocaine on his first try, Mr. Cash said.

Federal agents set up round-the-clock surveillance, obtained search warrants and brought in audio-video and X-ray equipment.

The whole shipment was unloaded to a warehouse in St. Petersburg. A few days later, 224 bundles of 24 boards each were transported to Mr. Tsalickis' Tarpon Springs warehouse, authorities said.

Mr. Merkle said the cocaine-filled lumber was found at the Tarpon Springs site, not in the wood left behind in St. Petersburg.