Like other major armies of World War 2 (1939-1945), the Soviets evolved one of their existing combat tank systems into a self-propelled flame-projecting platform. This came in the form of the KV-1 Heavy Tank series (detailed elsewhere on this site) modified for the role in 1942 as the "KV-8". The Tank was essentially faithful in form and function to the original KV-1 design but installed the ATO-41 series flamethrower next to the coaxial machine gun fitting (7.62mm BT). As this new arrangement reduced internal space in an already-cramped turret, the original 76.2mm main gun was replaced with the smaller 45mm Model 1932 series anti-tank gun.
In an effort to fool the Germans, the 45mm gun barrel had the gun tube of the 76mm set over it, allowing the KV-8 to retain the appearance of a true KV-1.
Internally there was still a crew of five operatives. The vehicle weighed 52.3 tons and showcased a length of 6.79 meters, a width of 3.32 meters and a height of 3.65 meters. Power was from a single V-2K V12 diesel engine developing 600 horsepower and allowing for road speeds of 35 kmh to be reached with an operational range out to 160 kilometers.
Approximately 42 KV-8 vehicles were produced. Twenty-five appeared as the KV-8S and based on the KV-1S production model (an upgraded version of the KV-1 with reworked turret, uprated transmission and better performance). These carried the ATO-42 series flamethrower as well which was an improved version of the earlier ATO-41. The KV-8M followed as a proposed, upgraded variant of the KV-8S model intended to carry two flamethrowers. Only two prototypes of this form were built and the design was not adopted for service.