Diesels do indeed have electronic injectors, the 5.9 just one year after that ‘02 you rebuilt has ‘em even.
I don’t think anyone said there is a gas six in a dually available new today, just that it would work.
Before anyone disagrees and thinks you “need” more than that, let me remind you GMC used to put their 305 V6 in theirs, and Ford used to put the 300 straigh-six in F600s.
I used to drive a tow truck that was a 300-six F600, it pulled a lot of weight a lot of places. Not at light-speed but it did it and didn’t break.
I used to haul my camper and trailer, totaling 22,000 pounds, with a 6.2 Chevy diesel. It had less power than the starter motor on a new truck. I did yank it out and put a big gas engine (Olds 455) in its place but even that didn’t have the power of a new V6 today.
I agree 100%, it’s all about ego, or just fun. I have a heavily hot-rodded Cummins - because it’s fun.
That truck only had barely over 200hp when it was stock and would have gotten my camper and trailer wherever it needed to go. You don’t “need” an 800 ft/lbs diesel. They’re just fun.