To start with, the new 6. 7 will be found, only, in the new Chassis/Cab configuration, along with the Aisin 6-speed auto (if you choose an auto).
The 2500/3500 pick-ups will still get the 5. 9 along with a new DC built 6-speed auto, 68-RE, (if you choose an auto). At this time, I don't know if/or when the 6. 7 will be available in the 2500/3500's.
My guess is that DC would not have spent the time & money in developing the new 68-RE, only to dump it in favor of the new Aisin trans. , after a few years. I could be, easily, wrong on this point, though. "Rumor" has it that the 68-RE will be a stronger unit than what is currently available.
Many pick-up buyers respond to the "Horsepower Wars" going on between Ford, GM & Dodge. Since the 5. 9 will have more HP than the 6. 7, they may be around for awhile, in the pick-ups. The 6. 7 will have less HP than the 5. 9 because that is where the best fuel economy is & the Chassis/Cab will appeal to commercial applications more than the general public. Commercial buyers are more interested in economy than having the highest horsepowered truck, on the block.
It should be very interesting to see what Ford, GM & Dodge will provide us. New emmissions equipment, horsepower/torque ratings, turbo configurations & number of turbo's (Ford), transmissions & fuel economy ratings should keep us occupied, for awhile.
Joe F. (Buffalo)