My truck all stock with a cat doesn't smell much at all. I think the allison is great though, tow haul mode really slows the truck down with a load. If the truck was well taken care of, I don't see it being a nightmare. Any of the gen 3's can drink oil. 8.1 should have good low end grunt like you want.
https://southjersey.craigslist.org/cto/5485683103.html
If that truck isn't rusted out......
