3UZ Swapping Our Lexus IS300 (Build Series Part 1)
3UZ V8 Swap Lexus IS300 Build Series Part 1 Engine Bay Teardown
The time has officially come. We are starting our 3UZ V8 swap Lexus IS300 build, marking the beginning of a full Toyota V8 conversion. This project focuses on reliability, OEM level engineering, and real world performance, all while keeping the build fully Toyota and Lexus powered.
In Part 1 of the Lexus IS300 3UZ swap build series, we begin the teardown process. This stage is critical for preparing the chassis and engine bay to accept the Toyota 3UZ FE V8. Every step is carefully planned to ensure proper fitment, clean wiring, and long term reliability.
Why the Toyota 3UZ FE V8 for the Lexus IS300
Choosing the right engine is one of the most important decisions in any engine swap. The Toyota 3UZ FE V8 is a popular choice for Lexus IS300 swaps due to its all aluminum construction, smooth power delivery, and proven durability.
The 3UZ FE is a 4.3 liter V8 originally found in Lexus performance and luxury platforms. Compared to heavier iron block engines, it helps maintain balanced weight distribution in the IS300 chassis while providing the torque and sound expected from a naturally aspirated V8.
This engine was chosen because it offers strong reliability, excellent aftermarket and OEM support, and seamless compatibility within the Toyota and Lexus ecosystem. For a street driven performance build, the 3UZ FE is an ideal foundation.
Radiator Support Removal for Engine Swap Clearance
One of the first major steps in this Lexus IS300 V8 swap is radiator support removal. This process allows full access to the front of the engine bay and makes engine removal and installation significantly easier.
Removing the radiator support creates the clearance needed to pull the factory drivetrain and later mock up the 3UZ FE V8. All cooling components are removed, labeled, and stored to ensure everything can be reinstalled correctly once fabrication and test fitting are complete.
This step plays a major role in simplifying future stages of the swap.
Lexus IS300 Engine Bay Teardown
With the front end opened up, we begin the full engine bay teardown. Factory components that will not be reused are removed to make room for the V8, including brackets, unused hard lines, and accessories that interfere with exhaust routing or accessory placement.
Cleaning and simplifying the engine bay at this stage allows for better fitment planning, improved serviceability, and a cleaner final appearance once the 3UZ FE is installed.
Wiring Harness Removal and V8 Swap Preparation
Wiring is one of the most complex parts of a Lexus IS300 engine swap. In Part 1, the factory wiring harness is removed and prepared for integration with the Toyota 3UZ FE V8.
This includes disconnecting and labeling connectors, separating engine and chassis wiring, identifying circuits that will be reused, and planning a simplified routing path. Proper wiring preparation early in the build helps prevent electrical issues and ensures a reliable final setup.
What to Expect in Part 2 of the 3UZ Swap
With the teardown complete, the build will quickly transition into mock up and fabrication. In the next part of the Lexus IS300 3UZ V8 swap series, we will focus on engine bay cleanup, initial engine placement, mounting considerations, and drivetrain clearance.
This is where the project starts to take physical shape.
Lexus IS300 3UZ V8 Swap Build Details
- Car Lexus IS300
- Engine Toyota 3UZ FE V8
- Transmission is still TBD
Follow the Lexus IS300 3UZ V8 Swap Build
If you are interested in Lexus IS300 engine swaps, Toyota V8 conversions, or 3UZ FE performance builds, make sure to follow along. This series documents every step of the process from teardown to completion.
Like the video if you are excited for the swap, leave a comment with questions or advice, and enable notifications so you do not miss the next part of the build. The Lexus IS300 V8 swap is officially underway, and this is only the beginning.