Jack J. Blank, 79, a retired Washington automobile dealer who had been active in local civic and charitable organizations, died Monday at the Washington Hospital Center following a heart attack.

Mr. Blank retired as president of Jack Blank Pontiac in 1969. He had owned and operated the dealership, first under the name of Arcade Pontiac, since 1937.

He began his automotive career as a salesman with old R.L. Taylor Motor Co. in the 1920s. He later served as manager of the old Lustine-Nicholson Chevrolet dealership in Washington for seven years before taking over Arcade Pontiac in 1937.

Mr. Blank had been a member of the board of directors of the Washington Metropolitan Police boys and Girls Club since 1937. He also had been the club's general campaign chairman since that time. He served as the organization's vice president in 1967 and as its president in 1978.

He was president of the Columbia Heights Businessman's Association and president of the Federation of Business Men's Association in Washington in the 1940s.

He also became known in the community for donating an automobile to Powell Junior High School in Washington for students studying mechanics and for hiring members of the Washingtn Redskins football team to work for him during the off-season.

He had been a member of the Greater Washington Board of Trade, The Washington Automotive Trade Association and had served on the old commissioner's advisory traffic committee for the District.

He was a 32nd degree Mason and a Shriner. He was a member of Columbia Lodge No. 3, and the Scottish Rite.

He was a past potentate of Almas Temple and an emeritus board member of the Shriners Crippled Children's Hospital in Philadelphia.

Mr. Blank helped to organize both the North Washington and Shepherd Park Lions and clubs and had served as president of both.

He was a member of the Terrapin, Redskin and Touchdown clubs and the Woodlawn Country Club, and had been active in the President's Cup Regatta. He was a member of the American Police Hall of Fame and the National Press Club.

He was a member of the Adas Israel Synagogue and of B'nal B'rith.

Mr. Blank was a native of Washington and attended McKinely High School. He served in the Army on the Mexican border before World War I. sHe was not allowed to go overseas during World War I because the Army said he was too young.

Survivors include his wife, Zelda Brown Blank of Washington: a brother, Meyer C., of Chevy Chase, and two sisters, Jean Pemstein of Silver Spring and Bertha Hirsch of Washington.