Don't know about the 767-400 specifically, but I doubt it's any faster than it's predecessors. The A330 is a fast jet, whereas, like you say, the 767 is notoriously slow. I avoid them on long flights cos it's an extra hour (not like the A340 vs 747 debate, where the 747 might save an extra 20 minutes on a long flight). The 767 is outdated, who is buying them other than Delta and a few for Continental?
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz