Comparing: KV-5 vs. IS-6

Development was started in June 1941 at the Leningrad Kirov Plant and completed by August, but the German invasion prevented development from progressing to the prototype stage. The KV-5 was expected to share some components with the KV-1. A new turret was designed, incorporating the 107-mm ZIS-6 gun. Early plans called for a new 1,200 hp diesel engine, but later adjustments, recognizing wartime disruptions, replaced this with two V-2K engines.

Plans for this vehicle were drawn up in the construction bureau of the Chelyabinsk Kirov plant from December 1943 to the summer of 1944. Further development and the construction of the first prototype took place at the Uralmash plant. However, the vehicle had no advantages over the other heavy tank designs under consideration, and its armor was seen as inferior to the IS-4 (Object 701), so the IS-6 was not selected for production.