I know the B-52's are powered by the TF33 engines. Those are a derivative of the JT3C engines.
I believe that Pratt & Whitney developed the JT8D as a "replacement" for the JT3C series. They both have similar thrust ratings. I also have read that the JT8D has been used by FedEx to replace the two outboard JT3C's on the 727's.
Would it be more cost-effective to replace the 8x TF33's with 8x JT8D's rather than the current Boeing proposal of 4x RB211's?
I mean to go from 8 to 4 wouldn't there be a lot of expensive re-design work for the spars and the such? I assume that the JT8D's could be almost as simple as a drop-in replacement?
Granted the JT8D's aren't as fuel efficient as the RB211's would be, but they'd have a lower re-engine cost, I think. Quicker return on investment?