My Bad valley. My brain fared on me ther(been doing that alot lately haha)
The mechanical injector pumps are simple to turn up with a aftermarket feul pin/ plate and a straight pipe with or without a muffler Wakes the motors up. If you get one with computer controlled systems there is a fairly decent selection of programs and chips that can get a few extra ponies out.
For fords 7.3 motor the 99 and newer motors have really good programs for them offering tunable hp settings from 50h-190hp (depending on the chip)
Pairing the mods together will get you enough power. Especially with the 7.3 turbo and 5.9 cummins.
Haha, no big deal, I wasn't posting just to correct you, but I was wondering.. 8.5? haha.
The 8.3L, the C series Cummins... big brother to the B series is a great motor too. We had one in the Timco feller buncher. Also in the long log truck and short log truck. The long log truck is loaded to 80k, and probably more sometimes (no scales) and it pulls the hills pretty decent. Shoot the 14 liter 855 Cummins in my firewood dumptruck makes about the same power (well... it did stock
)
Anyway, Urban Logger... not sure exactly what truck size your looking into, but if that truck is in the under maybe 20k when loaded down area and you live in a fairly flat area, and don't expect to be able to keep up with highway traffic it wouldn't be a horrible engine.
I ran a C70 Chevy for a couple years with a "300hp" 427 tall deck. Loaded down with 6 cords of wood (roughly 45,000lbs total weight) it pretty much took a couple miles to get up to speed. The book rated it at 300hp, but sometimes it pretty much felt like 5 hp compared to driving something modern. I ran a 600hp Kenworth 900 with 18speed over the winter and wow, talk about pulling hills real nice!
I pulled loads all over the state with the C70 and a few times on some hills steep enough that I was ALL the way in the basement (had 20 forward gears and 4 reverse) 1st in both trannys, praying that I wasn't going to blow a trans or driveline (thankfully they were semi truck sized, but still!)
Something to consider too is a smallish motor that is working real hard won't usually have a real long life vs a bigger motor not working as hard.