Comparing: IS-5 (Object 730) vs. KV-5

The development of the vehicle was started in 1949 by the Design Bureau of the Chelyabinsk Kirov Plant under the supervision of Joseph Kotin. In 1950 a preproduction batch of 10 vehicles was launched. After the vehicle underwent all trials and received upgrades, it was adopted for service in 1953 under the designation IS-8.

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.