The B767-400ER and the B777 certainly do NOT have a common type rating. The answer is simple. The B777 is fly-by-wire, the B764 is not.
They do, however, offer similar cockpits, and switching between the two aircraft is made easier by this, but the two aircraft certainly do not have the same type rating, because of the different flight systems.
M88, 722, 732, 733, 734, 73G, 73H, 742, 743, 744, 752, 762, 763, 772, 773, 77W, 320, 332, 333, 345, 388, DH8, SF3 - want