I was looking at Pravda article about Libyan arms purchases, and and came across a photo gallery for the Soviet obyekt 279 heavy tank, which they mischaracterized as the T-10.
It comes in at about 60 metric tons in the late 1950s, which makes it a very heavy tank for its day, as does the 130mm rifled gun it sported, along with twin treads on either side to improve mobility.
Interesting, but by the time it hit test, the ATGM had largely eclipsed the heavy tank, which was replaced by the by the MBT, the T-54s on the WarPac side, and M-60, Leopard I, and the AMX-30, which were all at least 10 tonnes lighter, and the Centurion/Chieftain which was at least 10t lighter.
