LS3 Swapped H3T

[whylee]

Do the tranny oil pans interchange since ours has the special shape to clear the drive line.

 

[Mr. Incredibull]

Hey everyone, that's my truck! I will try to answer everyone's questions and then post a build thread later.

I used the LS3 instead of the L92 because:
1.) I got a smoking good deal on the LS3 from GM performance, $6500 delivered to my door.
2.) I will probably put a different intake setup on later, (maybe even a supercharger!)
3.) The LS3 (LS376/480) came built with a "hot" cam, better heads and a 2 year warranty.
4.) Over the low power 5.3L that was in it an LS3 is just ridiculous improvement in horse power and fit right in, no real mods needed to anything.

The tranny is the stock 4L60, so far so good but I will put he "Z" kit in it to beef it up if this one ends up giving out.

Before the swap dyno was 220 HP to the wheels and 100 some thing lbs torque/ after 440 HP and 300 some thing torque.

I ripped the stock exhaust out for the most part and replace with true duels, no cats and flowmaster super 40's. I used the stock manifolds that came with the new motor, dropped right in and flows good.

So far he truck runs like a dream, if I want to tool around town nice and mellow it does that just fine, then when I want to get stupid I can peel the asphalt up. 0-60 times are right around 5 seconds, not bad for almost 7000lbs!

Any questions just ask.

 

[whylee]

Thanks for joining us here. Im sure you will be busy answering alot of questions. I wish I had seen this before supercharging. I love my supercharger, but that LS3 is one hot motor. How was the install as far as what mods to make it all work without check engine light.

 

[cgalpha08]

Welcome!!

Here's another question, how easily did the ls3 mate with /talk to the computers or did you install new computers already programmed for the ls3?
What about the wiring harness?

 

[Mr. Incredibull]

Sorry I dont get online a lot...

I did put in the better torque converter, 300rpm locking, made all the difference. Also I just swapped the oil pan from the 5.3, bolts right on to the 6.2 no problem and lets everything fit. I’ll try and get under the truck with my camera and do a video. Learned a lot and will post a build thread when I have some time. Alsop want to take some 0-60 vids, it’s pretty incredible…

 

[Mr. Incredibull]

Welcome!!

Here's another question, how easily did the ls3 mate with /talk to the computers or did you install new computers already programmed for the ls3?
What about the wiring harness?

Another good point, used the same computer that ran the 5.3L and the same harness. I obviously had it professionally tuned at the shop that did the work. We actually tuned it up to about 525HP at first then came down a bit.

 

[cgalpha08]

Good to know that it basically bolts right up!

 

[Mr. Incredibull]

Thanks for joining us here. Im sure you will be busy answering alot of questions. I wish I had seen this before supercharging. I love my supercharger, but that LS3 is one hot motor. How was the install as far as what mods to make it all work without check engine light.

I was going to do the supercharger but waited too long and there are no more kits. I would have had to custom install. Overall the new motor was cheaper than a supercharger and about 150HP better. No mods for check engine light, the 5.3 computer can run the 6.2 no problem, just needed to adjust all the fine points of timing and flow.

 

[RamRod]

Very cool info! Thanks for posting up!

Can't wait to hear more!

I bought my Alpha with the supercharger installed already; recently I found the bill for the dealership to install the supercharger :holymoly

I am sure this would be the cheaper way to go if its just a drop in mod!

 

[High Five H2]

Awesome! hope you stick around, I'm sure there will be a zillion other questions for you. I have a ton. I have always wondered how much power the transfer case could handle. any idea there? one day I may call BW and see if they have any torque specs on it.

 

[06 H3]

Welcome aboard!

awesome build! I just swapped a 5.3L in place of my blown up 5 cyl with a hole in the oil pan. Then I saw your video and now I say why didnt I go to a 6.2??? lol

Either way its good to know a 6.2 swap will be easy in the future, or atleast easier then the 5cyl to 5.3 swap

 

[RamRod]

Welcome aboard!

awesome build! I just swapped a 5.3L in place of my blown up 5 cyl with a hole in the oil pan. Then I saw your video and now I say why didnt I go to a 6.2??? lol

Either way its good to know a 6.2 swap will be easy in the future, or atleast easier then the 5cyl to 5.3 swap

Now don't go beating yourself up too much!

going from a 3.5L to 5.3L is a huge accomplishment!

 

[06 H3]

lol nah, Im not beating myself up over it the 5.3 is great, I am glad that I found out a 6.2 is a relatively easy swap!

 

[Bigunit]

Welcome. Glad you joined us and are willing to answer all the questions about the beast rig you have there.

 

[Mr. Incredibull]

Awesome! hope you stick around, I'm sure there will be a zillion other questions for you. I have a ton. I have always wondered how much power the transfer case could handle. any idea there? one day I may call BW and see if they have any torque specs on it.

I think the transfer case will handle a bunch, I'm sure the tranny will give up before the transfer case. As long as you don't do burnouts on the pavement both should be fine.

 

[4speedfunk]

The front axle is already on death-row. By far its the weakest link. As long as you have an AAM-7.6, your tranny & t-case will be fine!

 

[Clarke]

Did you use the 5.3 headers or did those get tossed with the exhaust and something custom fabricated up? Looking forward to your build thread when you get the time!

 

[Mr. Incredibull]

Did you use the 5.3 headers or did those get tossed with the exhaust and something custom fabricated up? Looking forward to your build thread when you get the time!

The room is pretty tight on the side so we used the 5.3 stock headers. We did a side by side and both the 6.2 and 5.3 headers are pretty much identical. Both have 1 7/8 inch ports and the 5.3’s end in the correct place to start the run of the exhaust under the truck. The dang exhaust was much more work than the engine swap, there is just very little room to run pipe. To do it right you have to custom make everything from the header back. In hind sight the stock 2 into 1 would have worked OK, just split it back into 2 again at the rear but I wanted the true sound of duel exhaust. That and the stock Cats are right at the end on the headers so they had to go. We capped the O2 sensors so the engine management software wouldn't freak out.

 

[derian06]

So you're saying that everything bolted up and plugged in perfectly, and all you needed was a tune? What about engine mounts?

 

[High Five H2]

engine mounts are the same. externally, the 6.2 and 5.3 are identical. When I was comparing L92 (truck 6.2) and LH8 (alpha engine) the only difference was the crank pulley. I think LS3 would have different accessories on the front and that's it. I imagined accessories got swapped over?

I have dual exhaust on mine, too. I was cheaper to buy my own muffler and have a shop weld it up. Plus, dual exhaust is rad. I want to put headers on it eventually.

 

[Ghostbuster]

So the grand total for everything was close to $10k?

 

[jphh20]

This thread is making me think that I should continue to keep my 06 as a daily driver, but a used alpha with high mileage and make a similar swap with a sas. This would make one unique rig that would be like nothing else.


Sent from my iPhone using Tapatalk

 

[whylee]

Did you beef up the cooling system at all over the stock Alpha system.

 

[Mr. Incredibull]

So the grand total for everything was close to $10k?

As you know when you start building you pretty much never stop spending money but for the swap it looked liked this:

Engine delivered $6500
Engine installed $2500
Torque converter $ 500
Exhaust work $2000
Old engine credit <$1200>
Total $10300

The engine install included all the fluids, small pieces, misc bolts etc. I got $1200 credit for my old motor, (only had 60k on it).
I spent too much on exhaust cause I tried a couple different mufflers before I settled on the ones I wanted.

 

[Mr. Incredibull]

Did you beef up the cooling system at all over the stock Alpha system.

Nope, what was in there works just great. I can idle for hours or get on it hard and it never get above just under half way on the gauge.