Common Questions

The Info You’re After

How does it work?

The GM engine uses its own ECU and wiring harness. Our product works by sending appropriate signals back and forth between the two ECUs, transmission computer (TCU), ABS computer (SLABS), body control unit (BCU), and dash gauges. The GM ECU is also in control of fueling and emissions.

What features are retained?

This swap is designed to be as comprehensive as possible. The factory air conditioning, cruise control, ABS, Traction Control, Hill Decent Control, sport mode, and manual mode all work as if nothing has changed. The only feature that is not retained is engine torque management. During normal driving this does not typically change the shift feel of the transmission. This can be noticeable when shifting at high engine speeds.

What LS engines are compatible?

Most GM LS 3rd generation 4.8L and 5.3L small blocks should work. 6.0L engines are not currently recommended. GM 4th generation LS engines should also bolt up, but have not been tested. The kit does not support older GM engines such as the  Gen 1 small block. See our page about Engine Options.

What is my total cost for this conversion going to be?

If you use a quality used 3rd generation LS engine and follow our parts guide, the total parts cost for the conversion should be less than $5000. Adding headers or doing a top end rebuild on the engine will increase the cost. Clever shoppers could do a budget build with iron-block LR4 4.8L or LM7 5.3L for significantly less than the figure above.

What exactly will I have to buy to make this work?

A sample parts list with model numbers is available on the product page. In general terms, you can expected to need:

How long will this take to complete?

If your diligent, not much longer than a typical Discovery 2 engine swap. We've found that it is easier to put an LS engine into a Discovery than a Rover V8 once the wiring is completed. We typically estimate 35-40 hours for a shop with experience with the kit.

Will the stock transmission handle the power?

The ZF 4HP24 was also used behind BMW V12 engines in the 1990s and are rated for approximately 335 ft-lbs of torque. The 4.8L and 5.3L LS engines without modification typically make between 270 and 335 ft-lbs. We recommend making sure your transmission is in good condition before beginning a swap and changing the transmission fluid frequently. While we have not experienced any transmission issues related to this swap in our testing, we cannot guarantee that your transmission will survive any power increase. There are several rebuilders who can build a 4HP24 to take significantly increased power. For more information see the LS Performance page.

What about emissions?

All ACE products are sold for Off-Road Use Only. The GM ECU controls the check engine light and a second OBD2 port is added. Regulations typically specify that swaps are legal as long as the engine is of the same or newer model year as the chassis and it is the same vehicle type (i.e. light truck to light truck). All emissions equipment must be brought from the previous vehicle to the new vehicle. This, however, may not be true in your state or municipality. It is your responsibility to check with your local, state, and federal government to see what their expectations are before beginning the swap.

Will this work on my RRC or P38?

This kit was originally designed exclusively for the 1999-2004 Discovery 2. We are currently beta testing kits for the Discovery 1. While the bell housing adapters should bolt up, the motor mounts may not, and the accessory drive will probably need to be altered. RRC and P38 electrical systems are also different from the D2.

I have a 1999-2002 Discovery with a 4.0. Are there any other changes I need to make?

The earlier Discovery 2's had the ZF 4HP22 transmission while the later ones with the 4.6 had the ZF 4HP24 transmission. The 4HP24 was also used behind BMW V12 engines in the 1990s and can better deal with the torque that the LS engine is capable of producing. While the ZF 4HP22 is potentially capable of handling the power of the LS, it is advisable to change the transmission over to the larger 4HP24 for extra security. ZF 4HP24s are a fairly easy transmission to find in junkyards. There are several skilled rebuilders as well. For more information see the LS Performance page.

Where do you find a used LS engine?

LS engines are very common. We recommend using to locate a used engine at a junkyard near you. For more information see the Engine Options page.

Why do you need my VIN number?

In order to properly track our conversion kit sales, we have assembled an index of all vehicles with the conversion. If a customer wishes to sell their converted vehicle, we can confirm to the buyer that an authentic kit was purchased through us.

Where can I find help?

We can only provide limited install support via email. However, others that have completed the swap, as well as several threads with more information are available through Land Rover Forums.

©2021 Alternative Conversion Engineering LLC. See our Terms & Conditions. Alternative Conversion Engineering is not associated with Jaguar Land Rover. Discovery is a trademark of Jaguar Land Rover.