How easy is it to swap in a LS3 motor into a '00 auto?

**Mecinoid** · 09-07-2016, 11:33 PM

Just wondering how easy this is to do when the time comes for a new motor. Plan on keeping mine for another 20 years.

**Naaman** · 09-08-2016, 05:05 AM

I looked into this. From what I was able to learn it would be a significant job, including needing to update the wiring harness.

***SMWS6TA*** · 09-08-2016, 06:09 AM

You do have a ton of options with putting a new motor in.

If looking for the power of a LS3 you can also look for a 6.0L block like a LQ4 or LQ9 and built it cheaper than a LS3 BUT you can keep your wire harness, ecm & for a bonus use LS3 style heads & intake.

6.0L blocks are widely available and can be dirt cheap like mine was, I picked up a short block for $250. Most though are from around $600-1200 depending on your area. You can bore them out to at least 4.030", some I've seen a bit more but that required some testing of the block to make sure it could handle it. With 4" stroker crank you can have a 403ci (with a 4.005" bore) like mine or a 408ci (4.030" bore) or with some engine work on the cyl for clearance a 421 with a 4.030" bore and a 4.125" crank. Match that with LS3 style heads, custom grind cam, and LS3 FAST Intake and you'll have one hell of a beast.

The biggest PITA with going to LS3 is that you'll need to either get the wire harness & ECM with the engine and then have the harness modified to work with your gauge cluster or get a custom harness form Painless Performance. Both harness mod or new are expensive, Looking at around $650 or a bit more depending on which route you go. And you'll need the ecm to work with the engine because it's a 58x reluctor wheel. Our cars are all 24x reluctor wheel. There is a cheat in that you can press off the 58x RW and press on a 24RW. Doing it like that may be able to drop down the costs of harness mods some but there will still be a need to modify it.

My next major engine mods will be custom grind cam & LS3 heads as well as LS3 Fast 102 intake OR FI built.

**raynor139** · 09-08-2016, 06:24 AM

Not as bad as you think. Here's a write up on how to from super Chevy.

http://www.superchevy.com/how-to/0902gmhtp-chevy-camaro-z28-ls3-engine-swap/

http://www.superchevy.com/how-to/0903gmhtp-2001-chevy-camaro-z28-ls3-dual-disc-clutch-wiring-harness-install/

Go through the pictures they will give you more of the details.

Big things are reluctor wheel conversion most people just use the box that lingenfelter makes. Ls3 comes with a drive by wire throttle body so you got to convert that back to a cable driven style. Wiring harness which from everything I've read you can buy kits that plug into your existing one and a few other small things. Alot easier then it used to be. Alot of these parts can be sourced as a whole kit from a few vendors now a days.

***SMWS6TA*** · 09-08-2016, 06:27 AM

On the throttle bodies there are several venders that sell cable LS3 style TB's Nick Williams is one. I have his 102TB and it is a niece piece. No complaints at all.

**Mecinoid** · 09-08-2016, 11:42 AM

Very Kewl guys thanks for the info. My '98 is supercharged and only has 54K on it.

My '00 T/A has right at 100K so I think I will go with 6.0L block like the LQ4 or LQ9 and built it as SMWSTA6 suggests. I really don't want to deal with wiring harness swap.

From what I am hearing the LQ4 or LQ9 is plenty strong enough for street and strip use.
Do you think I can easily get 475HP+ out of that set up reliably?

**Whamhammer** · 09-08-2016, 12:30 PM

Originally Posted by Mecinoid

Very Kewl guys thanks for the info. My '98 is supercharged and only has 54K on it.

My '00 T/A has right at 100K so I think I will go with 6.0L block like the LQ4 or LQ9 and built it as SMWSTA6 suggests. I really don't want to deal with wiring harness swap.

From what I am hearing the LQ4 or LQ9 is plenty strong enough for street and strip use.
Do you think I can easily get 475HP+ out of that set up reliably?

475+ HP at the crank or wheels?

**Whamhammer** · 09-08-2016, 12:35 PM

If it wasnt for all of the extra stuff to convert an LS2 or 3 to work with an LS1 system (LS2 being simpler), I wouldve bought a bare short block by now. Now and then, part of me starts to weigh the difference in cost of a 6.0/6.2 aluminum block and the cost of resleeving the bores to 4.00-4.03. I bet the costs are pretty close.

***SMWS6TA*** · 09-08-2016, 08:24 PM

Originally Posted by Mecinoid

Very Kewl guys thanks for the info. My '98 is supercharged and only has 54K on it.

My '00 T/A has right at 100K so I think I will go with 6.0L block like the LQ4 or LQ9 and built it as SMWSTA6 suggests. I really don't want to deal with wiring harness swap.

From what I am hearing the LQ4 or LQ9 is plenty strong enough for street and strip use.
Do you think I can easily get 475HP+ out of that set up reliably?

Very easy...

My Engine Build
6.0L (LQ4) bored 4.005"
K1 Forged 4" Stroker Crank
Forged Pistons and I beam Rods
Polluter stg3 cam
Fast 102 Intake
NW 102 TB
LS3 injectors
Stock 243 Heads (no P&P or Milled down)

Going through a T56, 8.8 rear w/4.10 GR, my girl put down 450 RWHP & 440TQ at the wheel.

My biggest hold back is my heads. If I had a nice set of TF Heads I'd be real close to 500.

When the time comes I'll need to decide between staying as a NA or make the huge jump to FI. I do know I'll go to LS3 heads and Fast 102 LS3 style intake with a custom grind.

Now some info if you go shopping. Only difference between LQ4 and LQ9 is the pistons are dish, while the 9 has flat top. The 4 CR is around 9.4 while the 9 is 10.3ish CR. You'll want a 99-04 yr block so you won't need to address the reluctor wheel.

Quick way to identify what reluctor wheel you have is look at the Crank sensor. Black is 24x, grey is 58x. When you're ready hit me up I can answer most questions on the 6.0L blocks.

Last thing - LQ blocks are only 60ish lbs heavier than the AL blocks. Most AL blocks can't be bored out more than 0.010" some only 0.005" while iron blocks as stated before can handle 0.030" easy and if more some testing of the block. The other major bonus of iron blocks - more boost potential over AL blocks.

**Mecinoid** · 09-08-2016, 10:09 PM

Originally Posted by SMWS6TA

Very easy...

My Engine Build
6.0L (LQ4) bored 4.005"
K1 Forged 4" Stroker Crank
Forged Pistons and I beam Rods
Polluter stg3 cam
Fast 102 Intake
NW 102 TB
LS3 injectors
Stock 243 Heads (no P&P or Milled down)

Going through a T56, 8.8 rear w/4.10 GR, my girl put down 450 RWHP & 440TQ at the wheel.

My biggest hold back is my heads. If I had a nice set of TF Heads I'd be real close to 500.

When the time comes I'll need to decide between staying as a NA or make the huge jump to FI. I do know I'll go to LS3 heads and Fast 102 LS3 style intake with a custom grind.

Now some info if you go shopping. Only difference between LQ4 and LQ9 is the pistons are dish, while the 9 has flat top. The 4 CR is around 9.4 while the 9 is 10.3ish CR. You'll want a 99-04 yr block so you won't need to address the reluctor wheel.

Quick way to identify what reluctor wheel you have is look at the Crank sensor. Black is 24x, grey is 58x. When you're ready hit me up I can answer most questions on the 6.0L blocks.

Last thing - LQ blocks are only 60ish lbs heavier than the AL blocks. Most AL blocks can't be bored out more than 0.010" some only 0.005" while iron blocks as stated before can handle 0.030" easy and if more some testing of the block. The other major bonus of iron blocks - more boost potential over AL blocks.

That's about what I am wanting without the cost of a supercharger. I am into mine about 11K. I'd like to build a motor for about 3-5K with 500HP

Thx for the suggestions and pointers to potential big durable power.