They thought about it but decided it would be a waste of money. Lots of considerations go into engine choice and making changes is quite expensive. >In 1996,

They thought about it but decided it would be a waste of money. Lots of considerations go into engine choice and making changes is quite expensive. >In 1996, Rolls-Royce and Boeing jointly proposed fitting each B-52 with four leased Rolls-Royce RB211-535 engines. This would have involved replacing the eight Pratt & Whitney TF33 engines (total thrust 136,000 lbf (600 kN)) with four RB211 engines (total thrust 148,000 lbf (660 kN)), which would increase range and reduce fuel consumption, at a cost of approximately US$2.56 billion for the whole fleet. However, a USAF analysis in 1997 concluded that Boeing's estimated savings of US$4.7 billion would not be realized and that re-engining would instead cost US$1.3 billion more than keeping the existing engines, citing significant up-front procurement and re-tooling expenditure.