I think heavy tank is going the way of the battleship, in to oblivion. I would think India should build 35-40 ton light tanks which is a cross between tank and IFV. A smaller gun bore between 76mm and 100mm, ability to fire anti-tank missiles and having active protection system.
Yes, heavy tank is coming up for US And NATO country to go on expeditionary mission and screw up Muzzies in Iraq, Syria, Libya,Sudan may be Lebanon, Korea, Chinese coast. They want a tank which can bulldoze a building down to the ground. Take a direct hit of modern RPG and frontal hit of light missiles. They now want tanks for street fight.
They are they and we are we. Our tanks will go into Pakistan at desired areas to draw and destroy Pakistani reserves (mostly mechanised forces). Mobility, flexibility and firepower assumes greater weightage than protection. a 68 ton is big No No for such situations. Why be a heavy weight wrestler if you will not get up from a slush or loose sand.
Then you are making a tank which has this of Cummins, that of GE, that of Micron, that of kirloskar. No one asked you to be an assembler of Bombay Bhindi bazar.
Either you can make a tank or you can not. You can'make many things. No one is cutting your pay for that. If you can not get aside rather than spoil entire wargame. Make a tank and not a toy for Mapboard.
The entire drama is for earning commission in importing foreign parts and then assembling those, that too poorly.
User is the King. Everything is available for a price and your prices are higher.