Originally Posted by
unmanned_droid
I believe ground clearance is a major issue with a 4-engined B-52.
When I was involved in a B-52 re-engine exercise in the early 2000's, the leading contenders were the PW2000 and RB211-535 (i.e. 757 engines) - one per pod. While ground clearance was a concern, we had ways of dealing with it (one idea was getting rid of the outrigger gear on the wingtip and incorporating something into the outboard engine nacelles).
According to 'former' poster Ken V, the big issue with going with four engines was messing up the ability to carry wing mounted weapons.
Engine maintenance was not considered to be much of a concern. The time-on-wing between overhauls is so high on modern engines (15-20,000 hours between overhauls being pretty common) that the airframe would wear out before the engines...