The KV-220-2 was an experimental tank based on a lengthened KV-1 chassis, and was supposed to be powered by a version of the new M-40 engine. One or more prototypes were completed in the early summer of 1941 and supplied to the 124th Tank Brigade in October 1941. The KV-220-2 was armed with the F-32 76mm gun. The KV-220-2 was sometimes referred to as the KV-3.