Current wisdom on LS swap

[Jeff d]

I’ve owned TJs with the 4.0 for the last 24 years and have always wanted to put a V8 in one. My 18 year old daughter thinks it would be cool to help put in a Corvette V8 and I don’t have a good argument against it besides the 5.9L Magnum being an easier swap.

I think I may finally be ready to just do it. I’ve got a 2000 Sahara currently with the 4.0, NV3550, and Dana 44. I’d always thought I’d buy a 4 cylinder TJ to do the V8 to but I think this might be a better candidate. First of all, it’s a nearly pristine specimen of a TJ so it will be nice to own for many years with the V8 vs. a “clapped out” 4 cylinder that I find for cheap that needs all manner of other stuff addressed. Also, it’s got a transmission that can handle the power (at least for a little while) and an adequate rear axel. Finally my 4.0 is currently a runner with 85,000 miles on the clock so I can probably sell it to recover a significant portion of the price of the donor motor whereas a 2.4L would go to the scrap yard.

I think I’ve settled on wanting to do a Corvette LS III. They’re plentiful, it saves 100 lbs over the 4.0 and it would just have the cool factor. I’ve also successfully performed an LS crate motor replacement myself before, albeit on a GM vehicle that already had one in it. So, I’m confident I can do the electrical and minor fabrication necessary to put one in a Jeep.

Is anyone aware of any particular gotchas with a true LS III out of a corvette vs. the more typical 5.3-6.2L truck motor swaps? I do want to retain the AC so I’ll need to have custom lines made to match up with whatever compressor people are using on TJs (Trailblazer maybe?). I also think I’d delete the TJ ECU and set up a custom gauge pod with all analog gauges. Will all of the HVAC controls work without the ECU or do they require modifications to make them work standalone?

Is Novak still the only company making motor mounts that weld on and don’t require a body lift? I really like the proportions of the Jeep currently and would prefer not to have to install a body lift to clear the swap.

 

[CreepinDeth]

Have you read the LSx swap threads by members who have done it?? Start there

Ive done 2 LSx swaps into GM classics with the modern transmissions also, but that wont help me or anyone much with a Jeep swap.

Everything is unique to the vehicle receiving the swap

 

[Apparition]

The truck engines are iron block so if you want to save weight you need the aluminum version.

 

[Jeff d]

Have you read the LSx swap threads by members who have done it?? Start there

Ive done 2 LSx swaps into GM classics with the modern transmissions also, but that wont help me or anyone much with a Jeep swap.

Everything is unique to the vehicle receiving the swap

Yeah, I’ve read through them. Every one that’s documented is unique in its own way with variations in the donor vehicle and whether the stock ECU was retained. Also, the pre-fabbed parts available change over the years so I didn’t find much current, definitive info on how to accomplish it without a 1” body lift and 4” suspension lift. I definitely don’t want that much suspension lift but I’d do the body if required.

 

[P man]

x2 on reading the "how to ls swap" here on the forum. It was one of the best how to's I've read in a long time.

 

[Jeff d]

x2 on reading the "how to ls swap" here on the forum. It was one of the best how to's I've read in a long time.

I’m going to re-read now that I’ve settled on a path forward. I just didn’t recall much definitive information on doing it with minimal suspension lift.

 

[Rickyd]

As far as the hvac,controlling the ac compressor is the only issue i can think of. But i haven't swapped one into a tj. The swap i did in my 70 k20 i left out ac.

 

[P man]

I’m going to re-read now that I’ve settled on a path forward. I just didn’t recall much definitive information on doing it with minimal suspension lift.

Per novak a suspension lift is not necessary when using their mounts

 

[CreepinDeth]

After doin a few LS swaps and goin in deep $$$ wise, I will just tell ya I dont see a real gain for a 4WD Jeep over say a 4.7L stroker motor.

Cost to gain for LSx just isnt there for most intended uses. Theyre not “go fast” vehicles which is what most LSx swaps are done for

If I was gonna do a swap into a TJ Id probably do a diesel swap personally. I like the idea of those 3.0L diesels , but again what is it you want VS what will it cost

Any kind of conversion isnt going to be as easy as youre hoping it will be. Lets just clear the air of that right iff the top

 

[Fluxor]

Barking second in my TPI SBC YJ on 40s and tons was super fun. Just saying....Not cheap or easy but very very fun.

 

[IOwnCalculus]

Aside from the rare FWD 5.3L that came in some W-body cars (which have the GM 60 degree V6 bellhousing pattern and not the typical LS pattern), there is nothing fundamentally different about starting with an aluminum block instead of an iron block. I would expect more swap kits to be designed around the truck accessory setup, but you can put any LS accessory drive on any LS as long as you swap all of it over, balancer included. All of the factory AC mounts on the LS are super low and tight on the passenger side of the block, which is a rough fit against the TJ's frame rail. I wouldn't even bother with it, just get a Kwik or Dirty Dingo high-mount Sanden compressor that matches the rest of your accessory drive.