There are 3 types of engines used on the 767s I'm flying these days...the PW4060, the GE CF-6-80C non-FADEC, and the GE CF-6-80C FADEC. I notice that the PW engines like to synch the EPRs. The problem with this is that often the N1s will be off by typically .5%. This is noticeable in the mid cabin. I have even seen one pair that were off 1.0%, but one of these engines had 2 fan exit guide vanes removed for maintenance, and I attributed the difference to this fact.
The GE engines match N1s and are not a problem. I believe we are now standardizing on the GE engines, which is very nice because the PWs take forever to start. Why do they take so long to start compared to the GEs?