To swap or top build?

[flandersander]

Hi all. I've got a 1997 gmc sierra with 257000km. It's getting tired and has the infamous intake manifold gasket leak. Dumping coolant into the oil.

So here's my question. I would like to know which would be the better option.

A) build the 350 up a bit. Bore it out, new pistons, head job, cam yadda yadda yadda. Looking at around 2500 for the engine doing the work myself.

OR

B) buy an LQ4 and 4L80E out of a 2003 ish 2500 gasser and swap it out.

I found a local pick n pull where I can get a complete engine from intake to pan for $225. Any engine I want in any truck. Plus a 4 speed tranny goes for $125. $350 for the pair. Plus ECM, wiring, motor mounts and all the miscellaneous parts I'm thinking I can get away at about $1500 beans.

I'm a large truck (semi) tech and know my way around a motor, but haven't swapped a motor before. Rebuild a few times but never anything like the 6litre swap.

So with that all in consideration, which direction shall I go? This truck is mostly a putt around town truck. Will be lifting it 6" and 35s eventually. I hunt with it, tow the boat, etc. kinda an all around truck. I'm looking for some get-up-n-go but with decent mileage as well.

I imagine the 6.0 with the 80E would be more durable. Better for towing, more power and better mileage. And as I type this it makes me even wonder why I'm asking, but swapping motors scares the heck outta me. I hate electrical gremlins. I understand Nelson's makes a stand alone wiring harness that allows me to darn near plug n play. I would need the ECM from the new truck, but other than that its just hooking up plugs, supplying a ground, constant and switched power and away I go? Seems too easy. Anyway, looking for a little insight to the difficulty of the swap vs just building the 350 and the price of each. Seems like the swap is my best option for what I want and would be the least costly of the two. Dollar wise anyways. What do you think?

Edit: oops guess spell check didn't realize top isn't the word I wanted there. Haha

 

[92GMC]

Definitely do the 6.0/4l80 combo. You won't regret it. The next 400 I get will get that combo if I can find a deal on it

 

[92GMC]

Also visit ls1truck.com

 

[flandersander]

Well I've definitely got a deal on one. Its a sweet combo? I'm not 100% sure. I've been looking into exactly what I need. Looking like the 411 ecm, the engine tranny and all the associated goodies like intake exhaust manis etc. That nelsons stand alone harness is where I think ill go. But the website is rather vague.

 

[eric.s.t]

What kind of question is that!? lol definitely go with the 6.0L for sure. Never done the swap myself, but never heard bad things about it.

 

[JollyGreen]

I've never done the swap, but if it was my money I'd put the 6.0/4L80 combo in it. You're getting so much more bang for the buck going that route IMHO.

 

[flandersander]

So I've been compiling a list of parts I'll need.
From donor truck:
Engine
Tranny
Transfer case???
Ecm???
All wiring on engine side of firewall
Intake and maf
A/c system
Alt.
Any other little goodies.
Out of catalog.:
Nelsons harness (not sure about nbs or obs ecm)
Motor mounts
A/c mounting bracket? Can I use the donor ac or do I only need this bracket if im using the compressor off the 350? Unclear about this one.
New drive shaft (maybe)

Will I need a new tranny xmember or can I use the original one?
If I go dbw I guess I'll need the pedal and associated wiring.
I'm loaded with questions, but thats all I've got for now.

 

[flandersander]

Okay, so after some more research, I think I've decided to integrate the nbs PCM as minimally as possible. Ie) only running the engine and trans. Keeping the original PCM controlling abs, tach, speedo lights signals etc. when doing this, I realize I will need to supply the nbs PCM with the data it needs to properly run the engine and trans. Is that where the stand alone wiring harness comes into play? Then the custom tune is to allow the nbs PCM to ignore some inputs it's not getting and to bypass security features etc etc. correct?

Or I have the option to swap my current PCM to the 0411 service# then run the LS right off the existing (now swapped) ECM.

I've reached an impass. Not sure which way to go. As stated I think I'm going to keep my obs PCM and run the engine separately. Unless there is a reason to swap to the 0411 PCM and ditch the obs one? Maybe I just need to pick one and run with it. But I guess I don't know the pros and cons of each. Which route would you take? I'd like to make this somewhat plug and play. Or as much so as possible. Hence me leaning more to using 2 PCM's. Thoughts?