Originally Posted by
DaveReidUK
There were of course some 60 or so 727s, mostly -200s, that were partially re-engined with the re-fanned JT8D-217/-219 (the centre engine remained the original one as there wasn't enough room in the bay).
Perhaps hearsay, but I was told that Pratt wanted to go with a larger fan on the JT8D-200 series, but was limited by the center inlet capabilities (apparently Boeing was willing to re-engineer the engine mount for the larger fan, but not the S-duct). Going with a larger diameter fan would have given the JT8D-200 better fuel burn and perhaps a bit more thrust capability.
If true, Boeing actually managed to hurt the performance of the MD-80
