ls 4x4 swap questions

[marc55]

I have tried to find some info about transmissions and transfer cases options on an Ls swap and have not found what I am looking for. My project is a 55 Chevy body on a 78 4x4 frame. I want to install a 5.3 engine and am wondering about controlling the transmission and transfer case. Can the engine harness be easily modified to control a 4l60e and a push button transfer case? Or am I looking at buying an expensive controller? I would like to buy a complete drive train out of something like a Tahoe but I don’t know how complicated it is to work with the vss system and I don't want to buy stuff I ca not use. My other option which I am leaning towards now is to adapt a 7004r to a manual np241. Also on the 78 frame are there any issues with the oil pan clearance?

[BR3W CITY]

The ecm can run the motor, trans, and late model transfer cases, so buying the package together is a decent prospect. I would at least try to source the engine and tranny components and accessories all together, then locate a different transfer case if its needed for your application. The stock wiring would work for all of it; though I can't vouch firsthand for how this works with non-gm transfer cases...I know little about them in general.

A 700r4 is basically a 4l60e, just not using computer control. Fitment wise things would be pretty similar.

The stock truck oil pan will hang a few inches below the crossmember. If thats not ok for your intended use (and/or you don't want to build a skidplate), then switching to the LH8 pan or Fbody pans might be better for you.

[Wasted Income]

A tahoe transfer case will not work with a 78 chevy chassis....the Tahoe has a driver side drop, and the 78 will have the diff on the passenger side.

I used a 5.3, 4L80E, and NP241 from an 91 blazer. I had to swap input shafts in the t-case to mate to the 80E, but it all fit together pretty nice. The 91 T-case also has a VSS reluctor on the output shaft to signal back to the PCM.

[whitels1]

Depending on the length of the whole set up, another cheaper option could be to run a 2wd trans with a divorced NP205.

[Big Port Jimmy 6]

Change the axles? Aren't Dodges D/S drop?

[marc55]

Thank you for the information. I think the early 90s suburbans are also passenger drop t case. Oil pan should not be an issue I am running 35s and not planning on off roading much. I also think I will be fine with the 4l60e if I do not have the change the input shafts. A lot of people say 130,000 miles is nothing on a Ls engine. I have read that you can not bore them out either. Should the engine at least get re-ringed and bearings? I have rebuilt a hand full of 350s but no nothing about the Ls platform.

[BR3W CITY]

130k isn't terrible on a stock motor. For a simple swap, just replace the oil pump and seals, water pump, and probably the thermostat/housing.

Whoever told you they can't be bored don't know what they are really referring to. If that was the case...how would gm have gotten 6 Liters from the same block as the 4.8?

[Wasted Income]

Yes, the 90-91 suburbans and crew cab 1 ton trucks also had the passenger drop T-cases....until the switched from the square body.

The aluminum motors are the ones that "can't" be bored. I think you can maybe take them like .010 but that's about the max, since they are sleeved.

The iron blocks can easily be bored just like any other gen 1 SBC.

I would not even worry about 130k miles. I've personally seen them go 300k miles with only the intake gaskets being changed. Most of my turbo and nitrous LS engines have all been 100k+ mile junkyard engines.

I've swapped 6 junkyard/craigslist LS engines in the past...have never replaced rings or bearings, or oil pumps....never had a problem. Only replaced water pumps twice...one was damaged, and the other was getting different front accessories. Take it for what it's worth.

P.S. The 6.0L block and the 4.8/5.3 block are different castings. I have never heard of anyone going to a 4" bore on one, much less the 4.030 that a lot of guys go to on a 6L block.

[whitels1]

Originally Posted by Wasted Income

P.S. The 6.0L block and the 4.8/5.3 block are different castings. I have never heard of anyone going to a 4" bore on one, much less the 4.030 that a lot of guys go to on a 6L block.

I currently have a 4.8/5.3 block on the stand that was bored to 3.90, so it is basically an Iron LS1. It was sonic tested by the machine shop and he said it was as far as he would safely go.

[BR3W CITY]

Originally Posted by Wasted Income

P.S. The 6.0L block and the 4.8/5.3 block are different castings. I have never heard of anyone going to a 4" bore on one, much less the 4.030 that a lot of guys go to on a 6L block.

Cross-section to cross section they are nearly identical sans the actual bore. If someone developed an aftermarket sleeving I wouldn't be shocked if it was possible. You can get VERY close to the 4" bore, though with the availablility of the lq4's, there isn't really a reason to dump money into trying. The ls4 is on the same cross section, just with a few slight variations like the bellhousing pattern. Same goes for the aftermarket blocks, which are still the "same" but obviously modified.

Strangely, the LSX motors WERE designed to be bored, and about 150 guys have already blown holes through the cylinder walls. Go figure. (and that is about the "least" like another ls block as they come)

[Special-Ed]

there is a guy in another thread that reclocked the cadillac transfer case to work with the lsx motor / 6l80e on a gen 1 4x4 blazer...

http://67-72chevytrucks.com/vboard/s...d.php?t=605688