Kv-1 does not have the gun to compete in AH with late war models, it share the same gun as the T-34 76.2 mm.
The Sis model KV-1 have favorable all around armor compared with the Sherman, and specially the Panzer IV.
KV1's series are early to mid war war heavy tanks, replaced with the IS-1, and to some extent with the KV-85, that reused the chassis of the KV-1, both with the same gun as the T34-85.