I was searching for info to educate myself on the 6.7 cummins. I already knew of the great reputation of the 5.9 cummins. I came across this article which seems to be straight forward and very helpful for anyone like me who wanted to know more.

https://www.drivingline.com/articles/59l-vs-67l-which-cummins-is-really-better/


Facts are stubborn things.