Detroit or Cummins

That's a roll of the dice. There are a lot of variables to take into consideration. The main thing with buying used is, what maintenance was performed on the engine.
The type of work the truck was used for climbing the "Rockies" or smooth sailing Florida. What type of work you're going to be doing? If you don't have a "verified maintenance report consider it wasn't done. This is just some things to consider and do a price check on all the major parts that would need to be replaced on each engine to compare. All the best on your journey

 

Cummins will be easier to permanently fix the emission issues you are going to have in that mileage range.

 

You can also take a cummins just about ANYWHERE to work on it.

 

The DD should get better mpg. I'd take that into account along with 1000 other things when looking at a truck purchase.

 

If you want to make sure of this look around and ask around. You'll see now is NOT a good time to become an owner operator.
The market is in the toilet.

There's no rush to get into this, it's better to stay company until things get better to consider o/o.

 

Why Ryder?

 

These fantasy topics by the OP are an entertaining read....

 

I'd take a Detroit over a Junk Cuminns anyday

 

I'd be more concerned about buying a 6-8 year old lease truck that's been thrashed on by dozens of drivers.