In reference to your earlier post, I found this on the Boeing website (it looks like the -400 can serve those Atlantic routes comfortably):
The 767-400ER is designed to be the most efficient airplane in its size category, making it an ideal replacement for aging L-1011, DC-10-30 and A300 airplanes. In growing markets, it can fly more passengers on routes served by existing 767s, A300-600s and A310s. Efficient design gives the higher-capacity 767-400ER excellent range capability (approximately 6,500 statute miles or 10,426 km) to fly more than 99 percent of the routes currently being served by airplanes in this size category.
. . .
The 767-400ER will fly all U.S. domestic routes. It also will serve North Atlantic routes such as Los Angeles to London, Newark to Moscow or Chicago to Warsaw. Other potential routes include New York to Santiago, Chile; Seattle to Osaka; and Atlanta to Honolulu.