Ted Kluszewski, the slugging first baseman who led the major leagues in home runs in 1954 with 49, died tonight after apparently suffering a heart attack. He was 63 years old.

Mr. Kluszewski died at Bethesda-North Hospital in Cincinnati, where he was taken after he was stricken, according to the Thomas Funeral Home. Career Average Was .298

Kluszewski, who was known as Big Klu, played 15 seasons in the major leagues, hit a total of 279 home runs and had a .298 career batting average.

He spent his first 11 seasons with the Cincinnati Reds and had his most productive years from 1953 through 1956, when he put together home run totals of 40, 49, 47 and 35.

In each of those years he also drove in at least 100 runs, including a league-leading 141 runs batted in 1954.

The left-handed slugger spent his last four seasons switching teams. In 1958 he was traded to the Pittsburgh Pirates and during the next season he was sent to the Chicago White Sox.

Although he only hit four home runs while with Pittsburgh and Chicago for 91 games that season, he made his only appearance in a World Series.

The Los Angeles Dodgers defeated Chicago in six games, but Kluszewksi had 9 hits in 23 times at bat, smacked 3 home runs and drove in 10 runs.

He stayed one more season with the White Sox before spending his last year in the majors, 1961, with the Los Angeles Angels. Couldn't Be Fenced In

Theodore Bernard Kluszewksi was born in Argo, Ill., on Sept. 10, 1924. The Reds discovered Kluszewski at Indiana University, where he played football and baseball. The Reds held spring training at the university from 1943 to 1945.

Kluszewski drew the Reds' attention because he was hitting line drives that broke through a wooden outfield fence. He signed for a $15,000 bonus in 1946 and was assigned to the Columbia team in the Sally League.

After he led that league in hitting with a .325 mark, he was promoted the next season to the Southern Association, where he batted .377 for Memphis. He batted only 10 times that year for Cincinnati, but by the end of 1948, he was the Reds' starting first baseman.

Kluszewski, recognized by his big forearms and large biceps, was one of baseball's most feared hitters in his prime. The 6-foot-2-inch, 240-pounder played on National League All-Star teams in 1953, 1954, 1955 and 1956.

Kluszewski returned to the Reds as a batting coach from 1970 to 1978, where he oversaw the hitters on the Big Red Machine teams under Manager Sparky Anderson. He became the organization's hitting instructor in 1979.

Kluszewski, who retired as the Reds' minor-league hitting instructor last year, had undergone bypass surgery after a heart attack in 1986.

He is survived by his wife, Eleanor. Plans for funeral services were incomplete.