There's a couple of problems I can see with this idea.
#1 The quality of the steel used back then.
#2 The amount of 'meat on the bone' after a rechamber to the X74 in the chamber's pressure chamber.
#3 The bore size isn't going to be the same as needed for the X74. I have 2 X72r' and the diameter is .363 and .365 on the different rifles.
#4 There isn't enough steel in the barrel bore to take out to bring it up to the .366 needed for the X74 because the twist is not going to be the same. IIRC they need .020 minimum for a re-bore and re rifle.
I would also suspect that the action would'nt be strong enough for the higher intensity of the X74.

If you want 'more get up and go', find another rifle and upgrade. It'd probably be cheaper and better.