Start of my rebuilld

[David623]

I have blasted and painted the frame, rebuilt rear-end (posi-trac 373). Also with fellow members help finished the front end, the dust shields painted up real nice. LMC new leaf springs front and rear.
Should be receiving new 5.3 motor (out of 2003 GMC) rebuilt. What motor mounts will I need? any help in that area would be appreciated. I also plan on using the overdrive transmission and transfer case, and the motors wiring harness and computer that comes with that motor.

[Jdubs71]

David,

Welcome to the forum. It looks like you have gotten a pretty good start so far. I too have picked up a 5.3 and still looking for a 4L60E for my blazer. The motor mount situation is a little different for the 4x4's so I have found out. The oil pan will not clear the stock crossmember. A few guys on the forum have built their own custom motor mounts or crossmember and others have used the crossmember fab'd by pacific fabrication here in CA. It's expensive, but they're a direct bolt in crossmember with only drilling needed. They seem to be the only ones who build this piece specifically for the 4x4 lsx swaps. I belive the guy there quoted me $399. I have been holding off, but will most likely end up biting the bullet and buying it. I keep holding off thinking something else will come out or that I may actually build one myself, just not that motivated.

As far as the wiring goes hopefully you got the harness and ecm in the package with the motor. In the research I have done you can either by a stand alone harness or have the stock one re configured for your set up. Both ways will still cost some $ unless you do it yourself. Not sure if you found the FAQ section for lsx swaps on here, but there is a ton of this information there and that has been a big help for me. Also check out ls1tech.com

Check out the link for more info.
http://67-72chevytrucks.com/vboard/s...d.php?t=456787

Justin

[SamMargritz00]

I sent my computer and old harness sent up to a guy in South Dakota, I can find his business if needed, but i had him custom tune the computer for 10% more power- comes to like 314HP if the factory numbers are correct- and had him make a custom wiring harness that had only the stuff i wanted for the engine and a couple other things and didn't have all the excess wire hanging from the old harness.

I built my own engine mount, wasnt too bad but im pretty good at fabricating.

i used a 4l60E transmission and an early 90's tcase so i could have the electronics but still have the driveline on the factory side.

all said and done i still get better mpg than the old 350 i had before, but I still only get 15 mpg with the 5.3. Someday i want to add an agressive cam and not worry about economy since i have my cummins i DD that gets better mileage.

oh and btw..WELCOME. looks like you got a very good jump on the project.

[Jdubs71]

Sam,
Would you happen to have any pics of the xmember you made? Does the tcase you used still allow you to keep the shifter in its original location? I think I may try to use my 205 since I just had it rebiulit. I would like the keep it in its stock location though and adapt it to the 4l60e.
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[SamMargritz00]

I read your post yesterday but I completely forgot to take some pics of it. Ill try to get it tonight for you.

[SamMargritz00]

heres my motor mounts and cross member.



Passenger side





Driver side






And as for the tcase shifter, idk if you can see in the last picture but it is in the factory location, but i cut the shifter down so it would fit under the dash because the different trasfer case has a different pattern. But if i remember right there had to be a little tweaking for it to be there, but don't hold me to that cause I cant remember, Id have to get under and look, this project has been spread out over the last few years and that was near the begginning.

[mcmlxix]

Pacific Fabrication has a bolt in LSx set up for 4X4...
http://67-72chevytrucks.com/vboard/s...d.php?t=487797


stolen from another thread listed in the above link...
Factory on top (too narrow)
PacFab on the bottom...