He was promoted to lieutenant colonel on 21 January 1943 and his unit was responsible for testing the M18 Hellcat tank destroyer, still attached to the 4th Armored Division.

[3]: 80–1  In August 1944, Delk was reassigned to command the 35th Tank Battalion, also part of the 4th Armored Division.

He returned to the U.S. and served as Plans officer on the General Staff at the Pentagon from April to August 1946.

He attended the Command and General Staff College at Fort Leavenworth from August 1946 to June 1947.

He then served as assistant commandant of the Army Aviation School at Fort Rucker until June 1961.

From June to October 1961 he served as a member of the Hoelscher Committee on reorganisation of the Department of the Army.

[1] He served as Commanding General, U.S. Army Aviation Center, Fort Rucker from March 1967 to September 1970.

[8] His decorations included the Distinguished Service Cross, Distinguished Service Medal (2), Silver Star (2), Legion of Merit, Soldier's Medal, Bronze Star (2), Purple Heart (2) and the Croix de Guerre (2).