Got offered another engine

Buy it, swap it in then have them rebuild yours and crate it if you have the cash, if the other engine is fine, run it till it needs a rebuild, then swap to your pre-rebuilt, if cash gets tight while your other engine is running good, a rebuilt engine ready to go shouldnt be hard to sell

 

4k$ for a builder engine
2500$ labor

 

I can get you 3406e with 13 speed for 10k , 350k with paperwork, it's still in truck

 

Lots of issues with good runners. There was a reason it was pulled to upgrade usually. I’d think your money ahead to rebuild what’s in place. Which is still not really knowing what you have in a sense. If you was to find an issue in the tear down and inspection process of yours that is a deal breaker or iffy then by all means it’s time to chance a used engine.

Even one that they can start and run a minute in a stand is really just a core engine. If it’s not mounted plumbed and hooked to a dyno so you can twist it up, warm it up and confirm it isn’t without issues it’s a core. Mileage is good to know but means very little. How many low mileage rebuilds you see have a catastrophic failure way too early? I’d say almost 50 percent maybe. Though I will say if they have 100 to 150k trouble free miles since a rebuild I feel better about them than a fresh un proven rebuild.

 

Everything @woreout said is true. But that engine may have been just pulled out of something that was wrecked, rusted, or broken in other ways that have taken that truck out of service that have nothing to do with the engine itself. That kinda thing happened all the time during the cash for clunkers debacle with vintage trucks.

 

I'm not exactly sure what your question is, but if you're asking whether to rebuild the engine that you have or to buy a used engine, I would definitely say rebuild the engine that you have if you can do that.

To me, on a big cam, 400,000 miles is a lot. You have no idea how much idle time is on it, how it was serviced, if it was turned up, who knows? You may even find that's a Frankenstein engine.

The other thing is anybody that's going to sell you an engine and tell you that it's a good running engine we can put it right into your truck and you can turn the key and it's a great engine, they're probably going to charge you like $4,500 for that.

Then they're going to charge you to install that engine. I don't know what they charge to remove and install I'm going to guess 1500 to $2,000?

By the time you do all of that you might as well just go over your own engine and when you're done you know you're a thousand percent.

The swap itself is nothing. The engines are identical one will pull out and the other one will go right in. The cabover is even easier.
Any big cam will swap into there, even an n14 will swap into there.

Used engines can be great. You just really need to know what you're looking at or bring someone with you that does, if you decide to go that route.

 

400K was the standard time to rebuild a Cummins. I wouldn't waste my time, and just sport for a rebuilt and move along.

 

Are you running a BC engine now? If so, a in frame kit is about $16-$1700. Probably your cheaper option if you go with a after market kit.

As far as the 350 the shop has, if you go that route I would get the numbers off the pump and check to see what it is calibrated for. Lots of BC Cummins out there with a tag stating what it came factory as, but the pump calibration tells another story….