local salvage yard had a 516 from an N7 a couple years ago and they didn't recommend me buying it as a replacement for my N6 426cid. I was told that it is quite a feat to convert the 426 combine engine to the 516, belts, sheaves, water lines, hydraulic pump and lines, and the list goes on. Before you buy, make sure you know the complete cost and changes that need to be done to the base machine. The Cummins retro fit is a much better match from what I have seen and heard. Good luck!