Originally Posted by
JPJP
I assume that the GEnx-1B from the 787 is out due to the lack of a bleed air system etc.? Then it becomes a massive undertaking to convert a 76-4 pneumatic system, electrical system etc. into a suitable configuration ?
The GEnx-1B is actually larger (bigger fan), heavier, and higher thrust than the -2B on the 747-8, so the -1B would be less suitable for a 767 regardless of the bleed architecture. Even the GEnx-2B is quite a bit larger/heavier than the CF6-80C2 or PW4000/94" (-2B fan diameter is about a foot larger), although the fuel burn is much better.
The GEnx-2B is already a significant derate from the -1B, if they derate it even more for a 767 installation it's on-wing time should be amazing.
Boeing originally proposed a 787-3 - it would have been shorter and lighter than the -8 model (and hence closer to a 767 replacement), but no one was interested and it was quietly dropped.