rated at . The boilers were replaced by eight superheated Yarrow boilers with a working pressure of . On her sea trials in December 1936, before her reconstruction was fully completed, Giulio Cesare reached a speed of from . In service their maximum speed was about . The ships now carried of fuel oil which provided them with a range of at a speed of . The center turret and the torpedo tubes were removed and all of the existing secondary armament and AA guns were replaced by a dozen 120-millimeter guns in six twin-gun turrets and eight AA guns in twin turrets. In addition the ships were fitted with a dozen 54-caliber Breda light AA guns in six twin-gun mounts and twelve Breda M31 anti-aircraft machine guns, also in twin mounts. The guns were bored out to and their turrets were modified to use electric power, a fixed loading angle of +12 degrees, and the guns could now elevate to +27 degrees. The 320 mm AP shells weighed and had a maximum range of with a muzzle velocity of . In 1940 the 13.2 mm machine guns were replaced by 65-caliber AA guns in twin mounts. Giulio Cesare received two more twin mounts as well as four additional 37 mm guns in twin mounts on the forecastle between the two turrets in 1941. The tetrapodal mast was replaced with a new forward conning tower, protected with thick armor. Atop the conning tower there was a director fitted with two rangefinders, with a base length of . The deck armor was increased during reconstruction to a total of over the engine and boiler rooms and over the magazines, although its distribution over three decks, each with multiple layers, meant that it was considerably less effective than a single plate of the same thickness. The armor protecting the barbettes was reinforced with plates. All this armor weighed a total of . The existing underwater protection was replaced by the Pugliese system that consisted of a large cylinder surrounded by fuel oil or water that was intended to absorb the blast of a torpedo warhead. It lacked enough depth to be fully effective against contemporary torpedoes. A major problem of the reconstruction was that the ships' increased draft meant that their waterline armor belt was almost completely submerged with any significant load. Ships Service Conte di Cavour and Giulio Cesare served as