WELLESLEY HILLS, Mass. (May 17)—American Biltrite Inc. had first-quarter net income of $350,000, a fourfold drop from $1.4 million reported for the like period in 1999. Sales fell 4 percent to $102 million from $107 million last year. The company´s Tape and Canadian operations´ results were up from 1999´s first quarter, but those were offset by a drop in sales and net income by Congoleum Corp., a 54-percent owned subsidiary, Chairman and CEO Roger S. Marcus said. Congoleum´s results suffered from weakness in the manufactured housing industry and reduced purchases by distributors in advance of a new product introduction, he said.