Gas will be much easier to get parts for. I searched around for months trying to find replacement heads for my 6.2 before stumbling across a machine shop that would rebuild the old ones. I was really close to pulling the 6.2 & dropping in a 383 crate motor.
I've pulled the same 5th wheel with a 7.3 Powerstroke, LML Duramax, and my current 6.0 Powerstroke. Sucked with all of them. If there's any wind besides a tailwind, the camper drags like it weighs twice as much. And in the TX Panhandle, there's about 1 day a month without 20-30mph winds!
Mine has a very tough time starting in any temperature close to freezing, even with all the glow plugs working. I think I may be down a few points on compression; maybe the same for you?
Not saying you should do it, but I run 315/75's on my K30 and my 60 F250 on stock steel wheels. I off road the K30 & have never blown a bead, although I don't air down.
I'm interested in this as well. My C30 was a factory air truck, but it hasn't worked in 30+ years; My K30 is a bare bones, non-AC unit. There is a guy in town with 2 late 70's squares, both full custom jobs, & both have the Vintage Air systems. This is the way I plan to go for both of mine...
I'd install a fuel pressure gauge. The VP44 can still function on very low pressure, so you want to know if your lift pump is failing. I installed a Raptor pump in place of the stock one & was very happy with it.
I just put the HD coils in the front of my C30 & it now sits about 5" higher in the front. Still can't decide of I want to stay with these or go to a standard set for just a factory ride height. The HD's are 35% stiffer than stock, & as it sits now, the shocks are all the way out. If you...