Airline Herks

[Beermonster58]

I salvaged the wings, engines and tail off my A400 which was damaged beyond repair. I'd thought about using two of the engines on a C-130.

[AeroplaneDriver]

Hercules  had Allison T-56  engines  at about 4,500 shp each.    Replace with a couple of RR Tynes at 6500 shp each,   perhaps?

There WAS a proposal for a twin-Tyne powered Herk.  Didn't progress past the concept stage, but the twin-Herk idea progressed far enough for a lot of models and concept art to be produced. 

https://www.secretprojects.co.uk/threads/c-130-l-400-the-twin-engine-half-hercules.1750/

[jcf]

The L-400 was to use the outer wing panels of the C-130 with added wingtip extensions.
A conversion would therefore would be relatively easy all you'd have do shorten the wing
is to remove the outer panels from the parallel sided inboard wing panels. The aerofoil section at the inboard end of the outer wing panels is the same as the wing root section.

Repositioning the engine nacelles would be more complicated.