Spec'ing a used truck

Your 6NZ is going to get about 4.5 MPG with a tail wind, so you already have the customers we all want.
All depends on you and your needs.
I just pull a box. I'm 78K about half the time. I'm not hung up on a certain tractor at all.
This is my first one I've bought from a dealer, not a L/P.
It's a Volvo 670, D13, 10 Spd OD. 488K when I bought it, very well maintained
Like you said it's a tool.
I drove for JBH and some other big companies and I noticed they pretty much all used the 435 HP version of whatever engine. It squeeze's fuel.
Even with cheap fuel 1MPG is 10 grand a year.
This drive train doesn't have the problems the Cummins or DD does.
When I got in it, I saw it had a dump valve for the suspension, sliding 5th wheel, and trolley brake. Too me, along with the maintenance, I said we're in business.
25K miles on it, so far so good. Doesn't use oil. 6.8 MPG average, idling A LOT, so as not to freeze to death.
And it rides SOOOOOOO much better than a shaker.
$53,500.

 

My dreAm truck is also a W9.... But pulling containers, I just don't see how I could fit and maneuver one in some of the places I go.....
When I was truck buying, I settled on a truck with Engine, rears and tranny that would be cheap to maintain and repair ( it's my first truck and after purchase only had about 15 k in bank)....man, I'm glad I did!!!!!!! Repairs were non stop the first year, (even after dealer paid for overhaul)......

Do I want a 13 speed 6NZ W9 flattop .....hell yeah!!!!... Guess that will be my next truck....in 3 years......

 

That's interesting you said that about the wheel base. I often wonder what someone would do with a truck that is five or six feet longer than mine. I barely squeeze into many receivers and shippers, not to mention what would happen to a truck that is sticking out 5 or 6 feet past mine at many truck stops.

 

Wear and tear is the first thing I look at, then Engine, tranny, rears in that order. Rear gears can be swapped easier than ordering new length driveshafts to swap a 10 speed to 13. Next is sleeper and wheelbase size, interior level, paint color, etc. These are my levels of priority. The further down the line it is, the more likely to compromise.