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Discussion Starter · #1 ·
I'm guessing this has been brought up before, but I can't seem to find much with the search.

I'm looking at buying an early 04 with the HO motor. The motor is toast in it, dropped a valve, toasted a piston, cracked block etc. Very not rebuildable. So that leaves me with the option of looking for a replacement engine. The broken engine will be sold with the truck, so I can steal any and all useable parts and accessories. But what I need to know is what years of engines will be compatible with the early 04 HO motor that's in it now.

Basically what long block can I use to make this truck run again? I can swap over injectors, cp3, whatever since I'll have it all with the motor that's in the truck.
 

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All engines from '03 to '15 are direct replacements.

Is it an '04 (305hp) or '04.5 (325hp)? If it's '04.5 the injector spray pattern is incompatible with '03/'04 and '07.5+ 6.7
 

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You can put an 04.5+ engine in there and it will run, just not as well as it could. Tuning the deep spray bowls and injectors tot he early computers is a bit of challenge but it can be done.

You are looking at $5-6k for a complete engine. A long block form various sources may be a better choice. Keep that in mind when buying.
 

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Discussion Starter · #4 ·
He tells me it's an early 04, ho motor.
 

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It doesn't matter that it's an 04 you can put any 5.9 common rail in and it will work. The 03/04 had better piston design and better cam and no cat. Much more fuel efficient.
 

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I have an 05 and have wondered this myself. I know theres differences in some of harnesses. I find it hard to believe you can throw whatever common rail in there. like that apps sensor for instance my 05 don't have it. Or the vgt on later models? Is anything common rail just plug n play like that?
 

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Discussion Starter · #7 ·
I'm assuming that you'd have to swap the turbo from the older motor. But I don't know about the rest.

So whats this about the injector spray pattern? 04.5 to 07 are different? As long as I get a motor with good injectors, will it matter? As long as the 04.5-07 has the correct injectors in it, it should run perfect, right?
 

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I'm assuming that you'd have to swap the turbo from the older motor.
You will want to keep the later turbo and make it a manul boost control. The HE351 on the 325 engines is a better turbo than the HE341 on the 305 engines.

Everything else has to come off the 305 engine and will transfer to the later engine. Harnesses, sensors, ECU, etc. If you get an 06-07 engine to will have to swap the VC and VC spacer as they are different.


So whats this about the injector spray pattern? 04.5 to 07 are different? As long as I get a motor with good injectors, will it matter? As long as the 04.5-07 has the correct injectors in it, it should run perfect, right?
Yes, it will matter. It will run but not quite right. The injector spray engle is matched to the bowl configuration, deep spray or re-entrant. The early injectors are 8 smaller holes, the later injector 5 larger holes. Timing, pressure, and duration are matched in the ECU for the angle\bowl configuration.

The early injectors can be matched to the later bowl and electronics easier than the later injectors and bowl to the early electronics. The travel time of the injection event and the spread pattern of the fuel is affected by all the parameters and the physical configuration.

Again, it will run but not quite right. A late engine into early electronics generates much more smoke on accelration and haze overall with stock fuel management and timing.
 

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I have an 05 and have wondered this myself. I know theres differences in some of harnesses. I find it hard to believe you can throw whatever common rail in there. like that apps sensor for instance my 05 don't have it. Or the vgt on later models? Is anything common rail just plug n play like that?
Believe it.

Any Common Rail is a direct swap. All you do is swap the harness you have on to the new engine, easy as that. Also the injector harness and valve cover/spacer for the '03-'05 is different and needs swapped.

If you get a 6.7, and use the 6.7 rail, you need an extension harness to reach the rail pressure sensor on the 6.7 rail; rail sensor is in the middle of the rail on 5.9, it's at the rear of the rail on 6.7. It's like $20.

If you get a 6.7, you can swap the turbo or try to make the VNT work; I have a VNT controller on my '03, but it's no longer offered. I would swap to a different non-VNT turbo if I were to do it again.

I'm assuming that you'd have to swap the turbo from the older motor. But I don't know about the rest.

So whats this about the injector spray pattern? 04.5 to 07 are different? As long as I get a motor with good injectors, will it matter? As long as the 04.5-07 has the correct injectors in it, it should run perfect, right?
Correct.

If you run the '03/'04 injectors in the '04.5-'07, you need to adjust the timing. I have them in 200% over on my '07 and she's damn near haze free. If they weren't so large, I suspect they'd be completely haze free.
 
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