For those of you searching for one of the gen 3 engines here is a great link that summarizes all of the vehicles that had one of the four versions.
I've summarized some of the more common vehicles that were made for the longest length of time since these will probably be the easiest to find for cheap.
The Silverado, Suburban, Sierra 1500, Yukon and Tahoe seem to be the best targets for this. 2005 looks like the last year that the gen3 was in the SUVs and 2007 was the last year that it was in the trucks.

• 2002-06 Avalanche 5.3 LM7
• 2003-07 Express van 5.3 LM7
• 1999-07 Silverado 1500 (had the 4.8l LR4, L33 high output version (only in the 4WD version of the truck) and the flex-fuel L59 as well)
• 1999-06 Suburban (L59 flex fuel version as well as the LM7)
• 2003-07 Savana Van 5.3 LM7 and 4.8 LR4
• 1999-2007 Sierra 1500 (all four versions of the vortec that are mentioned in the Silverado above)
• 1999-2006 Yukon (LM7, LR4 and L59)
• 1999-2006 Yukon XL (LM7 and L59)
• 2002-05 Escalade LM7
• 2000-06 Tahoe, only the L59 flex fuel and the 4.8L LR4
• 2003-05 Trailblazer EXT only the 5.3L LM4 aluminum block

Gen. 3 engines could be found in cars up until 2005 and most trucks as late as 2007 (LM7, L59, L33, LQ4, LQ9) and had a 24 tooth reluctor wheel. One easy way to tell which reluctor wheel you have is to look at the crankshaft sensor. If it’s black you have a 24x wheel; if the sensor is gray then you have a 58x wheel. If you aren't buying and ECU with your engine you might want to keep reading.

Reluctor wheel info:
The reluctor wheel (tone/timing ring/wheel) is on the back of the crank and is read by a magnetic sensor on the outside of the block near the starter. The magnet reads the teeth on the wheel and this gives the ECU accurate crankshaft position. The Gen III engines (LS1/LS6/LQ4, and early LS2) came with a 24x (24 tooth). So, why does all of this matter? Because the reluctor has to match up to your ECU if you want your engine to run. Some higher-end ECUs let you choose between 58x and 24x, but in most cases ECUs are programmed for a specific type. So, if you have an LS3 ECU then you need that 58x reluctor just like that older LS1 F-body computer will require a 24x wheel. (pasted from here)

 

Aluminum block LS engines are ~ 450 lbs
Iron block LS engines are about 110 lbs heavier -- so ~ 560 lbs

The engines this conversion currently supports are:

LR4: 4.8L Iron block/aluminum heads
LM7: 5.3L Iron block/aluminum heads
LM4: 5.3L Aluminum block/aluminum heads (my choice for weight and price reasons (most junkyards think they are LM7s and price accordingly), will have to change oil pan)
L33: 5.3L Aluminum block/aluminum heads (high compression (almost a mini LS6), higher price, low production volume)

And:
*L59: 5.3L Iron block/aluminum heads (flex fuel option -- *I prefer to avoid, more sensors)

The other critically important item (regardless of the engine) is the GM ECM. 1999-2002 had the red-blue 411 PCM, which was drive by cable. This is much easier to install in the Discovery. 2003-2007 used the blue-green PCM, which supported drive by wire. Some of the blue-green PCMs supported drive by cable (but these are rarer and typically only found in 2003-2007 vans). For drive by wire, you also must install the GM gas pedal assembly and the GM gas pedal ECU as well as have a different wiring harness and throttle body.

All of the engines above will run on a red-blue 411 PCM, as long as they have the appropriate cable throttle body and sensors. Depending on where you live, you may have to run the drive by wire system for emissions. We have run both trucks using the cable throttle up to this point. We’re working on the blue-green drive by wire setup now. There is significantly more to making this compatible with the Discovery than the drive by cable setup.

Anything past 2007 moves from Gen 3 to Gen 4 LS engines. Most post 2007 engines will not run on a red-blue or blue-green ECM without modifications. Gen 4 does not support drive by cable in most cases and is more expensive. It comes with other features to factor in like displacement on demand and variable valve timing, which add to the complexity of the swap and tune. We will move this direction eventually, but right now we’re sticking with Gen 3. For this specific swap, there are not a lot of advantages of moving from Gen 3 to 4+, mostly just more issues to solve.

The easiest way to find engines is Car-Part.com--Used Auto Parts Market. You can plug in your zip code and the year, make, and model of engine and it will find all of the closest options to you. The option it finds includes all compatible models. For example: if I put in 2004 GMC Envoy XL 5.3, it will find 2003 and 2005 compatible engines from Envoys, Trailblazers, and anything else that had that engine. Search terms:

LR4: 1999-2002 Chevy Silverado 1500 4.8 (drive by cable), 2003-2007 classic (drive by wire)
LM7: 1999-2002 Chevy Silverado 1500 5.3 (drive by cable), 2003-2007 classic (drive by wire)
LM4: 2003-2005 GMC Envoy XL 5.3 (drive by wire)
L33: 2005-2007 GMC Sierra 1500 5.3 L33 classic (drive by wire)

The car engines are a whole other ballgame. The accessory drive spacing is different and the cam is not setup for torque. In addition, they are much more expensive. In my opinion, the LS1 would be no better in this swap than a LM4 or L33 with a bigger truck cam from CamMotion or another aftermarket provider. I do understand the appeal of having a true “Corvette” engine in the Discovery though, and we’ll see about looking into that soon.

 

Thanks for the great summary, Ace.
So the most ideal, headache free approach to this is to stick with the 1999-2002 range of GM cars which would effectively restrict you to only the drive by cable engines.
A bit concerned with putting an engine of an older model year into a 2004 Disco since that might cause it to fail emissions. I guess that will be more important depending on local laws.

 

All of the engines above from 99-07 above can run well on the 99-02 red-blue drive by cable ECM and that is the easiest solution. Similarly the drive by wire blue-green ECM can work, but it is a bigger headache.

One way to get around this is to find a blue-green ECM that supports drive by cable. This is sometimes like finding a needle in a haystack, as they all look the same and junkyards mark them the same. I have been trying to find a reliable source for these special blue-green ECMs.

There are also other considerations to think about, especially with emissions. Some of the early truck models (mainly, but not limited to 99-02 LM7s and LR4s) had EGR and AIR. Some, like the LM4, never were equipped with EGR or AIR. Sorting out these issues is highly dependent on your individual state, so it is very important to figure out what they expect. I would call the local DMV or research online.

As always feel free to email me with specific questions through our website.

 

Hey Ace, any updates from the people that were sent the prototype kits?

 

Not yet

 

 

Here’s where we are with things:

1. First prototype is still running good. I have spent a lot of time optimizing the tune and now I think it is performing better than it ever did before. I believe I have found the battery drain issue – It actually was the aftermarket radio and amp that was in the truck.

2. Second prototype has been running well since its first start. This was the first of the “production” conversion parts. The fit and finish of these parts were a significant improvement over the original prototype. The redesigned motor mounts are a significant improvement over the originals in terms of dampening vibration. Things went together much more smoothly and I have a lot more pictures for the manual.

3. We did, however, run into some issues when working on the emissions system. All the original testing I did on 2003 and 2004 ECUs. The second prototype is a 2002. It seems that there is some differences between the 1999-2002 ECUs vs. 2003-2004 ECUs. I have found a solution to the problem, but it’s going to require some reworking.

As I have said before, this has been a fairly major undertaking and we don’t want to release something until we know it will be issue-free. There are a lot of parts to this kit, nearly all of which have to be custom-made. We should have some feedback from the early beta testers very soon.

 

Thanks for the update

 

Thanks for the update ACE. Just an FYI, if you need another tester, I'd be willing to install using your latest "kit". (no emissions needed here)
There would be no need for ECU tuning on your behalf as I have a very good local tuner who almost exclusively works with GM ECUs and tunes them for cams, heads, big turbos/supers, etc...

Look forward to hearing more.