The OKB-520 design bureau of Uralvagonzavod provided another design, the Ob'yekt 167, which was the Ob'yekt 166 with a new more powerful V-26 engine using a charger, developing 700 hp (522 kW). Two prototypes were built in the middle of 1961 and passed the trials. This time the GBTU decided not to wait for the new medium tank to pass trials and sent the Ob'yekt 166 into mass production in July 1961. The Ob'yekt 165 also entered service in very small numbers, under the designation T-62A.