Not quite true, Rainboe...
In the 744, the EECs (Electronic Engine Controls) synchronize the engines as well as control the N1, as long as the autopilot is engaged. Also, as long as the thrust levers are within about a half knob of each other, the same N1 is commanded for all 4 engines.
In the 742, however, it is a different story completely. On the runway the engines are stabilized at 70%, and the relative thrust lever positions noted. That relative setup is retained up to T/O thrust, with the FE doing final adjustments as required.
Also, jet engines DO need synchronization to minimize beat frequency vibrations. The closer the engines are to the fuselage, the more notable the beat freqs become.