The engine had an aluminum crankcase which included inspection ports, and a governor built into the camshaft timing gear; it was driven through a three-speed transmission with a clutch brake.

[2] One of the most distinctive features of the AC was its hood and dashboard mounted radiator (mounted behind the engine)[note 1] which was covered by a squared off bonnet of a coal scuttle pattern which had a small circular grille at the front containing the Mack emblem, all of which gave the model its distinctive appearance.

One innovation introduced in the AC was the positioning of the steering wheel at a 45-degree angle which greatly improved driver comfort.

[2] The Mack AL was a version of the AC model and designed specifically for distribution operations and firefighting equipment.

[1][2][3] During the war Mack delivered approximately 4,500 ACs to the US government who adopted it as a standard type, using 31⁄2, 51⁄2 and 71⁄2 ton versions.

[3][5] The AC proved to be an extremely enduring model for Mack and it remained in production until 1938, with a total of 40,299 produced, along with 2,819 AKs and 285 APs.