2017 Heavy Duty 2500/250 - Gas Engine Changes?

We have a winter friend that bought a new Ford and 4.30 rear to pull back this winter a new fifthwheel. he has had 350 and a 450 ford but bought a smaller fifth. He has the 6.2 gas engine. I will be asking him how it is but I know he will be happy. I am old and do not understand a pulling truck with 8 to 10 gears and a gas engine. I had an 8.1 gas and it was very good with the 4:10 but not as good as the duramax.
chevman