My swap. 5.3 into a 1990 3/4 ton 4x4 Suburban.

[y5mgisi]

Yep. Literally better in every way. I would say that $1500-$2500 is about average cost. And the wiring is somewhat involved but if you have ever installed a stereo or a set of lights in your truck and know how to read a wiring diagram, you should be ok.

[kp110477]

alright... seconds after posting up about whether or not I should rebuild the 350tbi or swap an LS in I saw this... my paints going to be around 2500... so for 1500-2500 I guess I can spring for the swap! Thanks for the motivation, I'll be watching closely. Please Please Please post as many pics and diagrams as possible. I'm new to wrenching all-together and need all the help I can get. Also, why a 5.3 vs. 6.0, is the 5.3 gonna have enough ass to push your burb?

[91Subbed]

I'm listening...
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[kp110477]

some great articles for all of the questions that I'm seeing in this thread:

LS Primer 1

LS Primer 2

LS 2 Tech

Hope this answers some questions.

[y5mgisi]

why a 5.3 vs. 6.0, is the 5.3 gonna have enough ass to push your burb?

Cost. The 6.0's tend to run about $500 more then the 5.3's. As far as it having enough "ass" to push the burb, the stock tbi 350 was rated at 190hp 300lb.ft torque. The 5.3 is rated at 295hp and 335 lb.ft torque. So im sure it will be fine. I do plan on documenting everything i do so it can make the swap easier for people in the future.

[kp110477]

"fine" say you... I say bad ass, I didn't know there was that much of a disparity between the two... WOW! 105 more horses could never hurt HAHA.

[y5mgisi]

Yea its significant! You should check out ls1truck.com. Lots of info there. And check all the build threads here in the lsx FAQ thread.

[y5mgisi]

Got my fuel pump and temp sender today!

[y5mgisi]

Spent about an hour today with the pressure washer. Looks much better but still a little to do.

[y5mgisi]

Got the new motor dropped in today! Also set the intake on to see how it will look.

[91Subbed]

Nice!!! Can't wait till see it complete!
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[BlueMagicSS]

Nice!!! Can't wait to see it completed.

[y5mgisi]

WIRING! Actually its going pretty good so far. I got rid of the tbi harness tonight. THere is still a few wires left over that go to the driver side that i have to figure out that i will probably be asking about here soon. Also mocked up the exhaust manifolds. The strange thing is that the passenger side clears super good but i might have trouble with the driver side! Anyway, you know me, on to the pics!











Left over wires.



Removed wires.



This goes to one of the injectors on the TBI setup. Wonder if this could be part of my problem? Screw it.

[91Subbed]

The wiring is what gets me! It's looks confusing.
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[y5mgisi]

In honesty it confuses me too! All i really did is disconnect the computer connectors and drag them the through the hole in the fire wall, then went through them one by one while looking at a pin out diagram that described what each wire on each connector was for, clipped out the ones i know i need to keep, and through the rest away.

[91Subbed]

That takes alot of patience.
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[y5mgisi]

Actually, believe it or not, what i did only took about an hour. Not bad considering this is all first time stuff for me!

[Mr. 250r]

I might be wrong here but I didn't think of the old fuel lines would work because of the pressure? And as for headers in the future? If so any ideas
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[y5mgisi]

I dont think i will ever go with headers on this truck. Its more of a stock style build. The old fuel lines are good to go pressure wise. They used the same(style)lines on higher pressure trucks. Just anywhere where there is rubber needs replaced with the high pressure fuel injection hose. I'll post pics and what i did for fuel lines when i get to that point here in a week or two.

[clinebarger]

Originally Posted by Mr. 250r

I might be wrong here but I didn't think of the old fuel lines would work because of the pressure? And as for headers in the future? If so any ideas
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The 87-91 Suburban TBI fuel lines work great, Ive been running a 90 model TBI tank & hoses coming off the tank on my 5.3L 85 Suburban for 7 years, no problems.

[91Subbed]

Speaking of headers...will the shorty block huggers fit the tbi engine? Or would the long tube headers work best?
A Lil off subject.
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[y5mgisi]

Ok I got all the wiring all figured out now and just need to finish it all.

[kp110477]

I missed if you said it already, what transmission are you going with? Do you think it's easier to adapt the transmission to the engine or the transmission to the transfer case / drive line. Is it easier to swap just the engine or to swap in the 4L60E/4L80E that is designed for the engine in along with the engine? I'm following your swap closely. Great job.

[kp110477]

Also, I was reading another ls swap into a 4x4 sub of our same generation (by 85burb... I think) and he had a lot of trouble getting the headers to fit. If you go with the stock exhaust manifolds, is it a lot easier, do they fit without notching the frame?

Edit: I saw that your stock exhaust manifolds fit, did you end up trimming the driver's side at all?

[y5mgisi]

I'm running a th400 trans. In my case it is way more easy to keep the existing trans and bold the new motor up to it. If you had a 700r4 it would be whatever way you wanted to go with it. New motor would bolt right to the old trans or tys new trans would bolt right to the old t case. As far as headers, there Is a thread on here about what hits and what fits. My stock 5.3 manifolds fit fine but it looks like 6.0 manifolds are different and will hit. Only thing I have to do on mine is modify the down pipe off the manifold to clear the bottom of the frame.

Got the new harness a little but installed last night!


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