KV-220 (Object 220) Experimental tank based on KV-1. Longer chassis (7 rollers per side). Armor – 100mm. New 850 hp V-2SN engine with turbocharging.

New diamond-shaped turret. 85mm F-30 cannon. One prototype was constructed in 1941. The tank was lost in battle.

The KV-220-2 had its turret removed (The turret and KV-220-2 were both used in the defense of Leningrad) it was fitted with a KV-1 turret and F-32 cannon. The tank was lost in battle, supposedly later repaired, and sent to a training unit.