A few more questions.

Here's a couple flatbed 0/0's that can help you.
@blairandgretchen
@Nahbrown

 

Get ready to spend everything you make on that old truck. I ran an old truck for 10+ years. Truck was great, fun to drive, but it was a money pit. All old trucks are. Doesn't even matter if you're able and capable of doing the wrenching yourself. You're going to be buying a lot of pricey parts and your offtime will always be working on your truck.

Having been relegated to a company ride for the past few years and being in brand new trucks since that time - there's something to be said for never having to fix anything on these new trucks. I mean you just hop in and drive it every week. The shop services it every 25,000 miles other than that nothing. It gets over 9 mpg hauling some heavy ### reefer loads going through redlights every day. Good luck getting a meager 7 from your old truck on the open interstate, probably more like 6.

It's hard to compete in an old inefficient truck that needs new parts thrown at it all the time against trucks out here doing 9mpg, 10mpg or even better like it's nothing. I didn't even know this until the other day ago they adjust the clutch in this automated manual transmission by hooking a laptop underneath the dash and clicking on the computer, you can hear the truck itself adjusting the clutch. You won't adjust clutch like that on an older truck it's waste of time/money crawling underneath it. There's just so many ways new is better. Take that for what it's worth and good luck, you're gonna need it

 

I'd listen to @rollin coal first, but to answer your question.

Neither, I'm a Detroit guy, they are cheap to fix and parts are easy to find. But, they don't have longevity. If you drive the hell out of it like I do, you're gonna work on it quite a bit.

N14, just no. Parts are hard to find, constant injector issues. But, easy to work on overall.

Cat is where it's at, all else being equal. Parts are more expensive, but easy to find. Slightly harder to work on than the other two, but still not hard. Longevity is much better than both that you mentioned.

Fuel mileage between all will be about the same stock. This depends on where you drive too. If you drive it hard, the Cat might get a little better than the other two, if you drive them easy, the Detroit or Cummins might have a slight edge. Not enough difference to matter.

Resale will be faster and higher $$ on a Cat powered truck, and slowest and cheapest with the Cummins.

There's a hell of a lot more to a truck than just the engine though. Lots of clapped out late 90's Freightliners out there, so don't just look at the shiny parts.

If I see a 1k$ steering wheel, 2k$ seat, neon lights inside, and chome on all the switches, but it needs brakes and tires, you know they valued looks over mechanical. I'd stay away.

You really need experienced eyes to look at a truck.

 

Mazel Tov, kiss the money goodbye. I (we) understand fully where you are coming from. Mirrors us in many ways, however, that was then, this is now, and I've been involved in trucking for 40 years, and most of us here will say this is the worst time to buy anything, and used trucks are the epitome of fleecing drivers. Since new trucks are way out of line for most, everybody is jumping on the used truck scene. That part is okay, but repairs approaching $200/hr., some things you just won't be able to do. Insurance. What the mechanics don't get, the insurance vultures will. Taxes, FUEL? How can you absorb $6+/gallon? I paid .79 cents with about the same mpg. The trucks themselves don't do much for me either, used iron and you'll never get ahead. Nickel and dime you, they will. If you are that set to go for it, I'd go a KWhopper, for resale, and the biggest CAT motor I could find. Generally KW is a respected make and O/Os that had them took good care of them. A Volvo or FL, not so much. So many GREAT company jobs, one of my former employers offering a transport driver, $28.50 to start, AND union benefits and can't find anyone. I don't know man, like marriage, we didn't listen either, but the big difference was, when we bought trucks, there wasn't so much to lose, AND we didn't have the luxury of a site like this to tell us what to expect. So we lost our shirts and got company jobs and lived happily ever after.. Please rethink this, eh? Remember, a mishap could hassle you for the rest of your life.