Swaping engine.

I had that same truck back then, but 13 speed. 5
Was either 505 or 515 horse can't remember. It would go though. Centuries were so much better than Cascadia's. Loved that truck.
Did you call Freightliner? Or ask the DD shop in the large city nearest where you hail from. S60 may or may not mate up to that tranny. '06 as long as you know you could never set foot in CA, do away with all the EGR, shop just reprograms your ECM.

 

Some 12.7,s had EGR,s and some 14,s were made pre EGR. I thank I would like the idea of building it as a pre EGR engine but we can not talk about that here. The 12.7 will go right in there but the electronics won't work with the auto and maybe parts of the truck. Then you need an electronics- Detroit wizard.

 

Because it is an RV, not commercial, does not require a CDL does not mean it it exempt for EPA regulations for the year it was made.
Detroit 12.7-your 14 liter had five different ECM versions, DDEC 1-5. There are also probably at least that many versions of the Ultrashift with their own control module. Then there are many variations in each of those and they must work together. Later models get into more complicated systems way over my head.
750k and lots of blow-by. Is it puking and or using lots of oil? It could go a million, some blow-by does not cause low power.
Good engine under 10K? Used of course and what is the warranty? Then when warranty is out and a liner has a bad 0-ring or pin hole you are right back in the same place with a wallet already about about 15k lighter. If the crank is good I would fix what I have or step up to a crate motor like cowpie has in has truck.

 

Agree with @BoxCarKidd. Too easy to get burnt bad on a used engine. It's one thing if your current engine is completely toast. But if it can be repaired/rebuilt, I would go that route. You'll have the same money in a rebuild as you would a swap. But only if the engine you swap in is indeed a good one. And who's to say it won't need rebuilt next year? Just my opinion. Use it or lose it.

 

Like Rusty pointed at, you need to check into an overhaul. you will be in the same if not less price range. with a warranty.

 

Check with Stewart and Stevenson, or your local frieghtliner dealer for an idea on an inframe. I think you will be surprised. then check with a quality shop on the swap your thinking about. that should just about make up your mind, for the amount you plan to spend versus how much it will be used.

 

I watched a video on how DD does a rebuild compared to how others do one. I mean you have to do it mostly right, or it just won't run, but the technics that DD uses, I'd get them to do it, or buy a DD certified rebuild.