New 8HP Adapter Kit for Lexus GS300 (1998-2005)

We are excited to announce our new adapter kit designed specifically for the Lexus GS300 (2JZ) platform. This kit allows you to swap the modern ZF 8HP transmission into your GS300.

Why the 8HP Swap?

The GS300 was never sold from the factory with a manual transmission and the factory A340 A341E automatic transmission was fine but we wanted something better.

We received a lot of request for this car because it's a really nice platform, comes with a 2jz, is luxurious and really fun to drive.

This upgrade brings a modern performance feel to the GS300 chassis.

The test car

After spending a lot of time in the MK3 Supra, MK4 Supra, Lexus IS300, and JZX90, I always wanted to try the Aristo/GS300 platform. I found a clean car locally for a good price — perfect test candidate!

This kit is very similar to our IS300 8HP swap kit released a few weeks ago.

All of our kits currently use the Dodge 8HP variant because it’s widely available in North America. The bellhousing on the Dodge 8HP70 and 8HP45 is large, but we were able to make it fit without major issues.

Just like on the IS300, we reused our custom stainless engine brackets to move the engine slightly forward and help with clearance.

What’s Included in the Kit

• Perfect Tuning 2JZ -> 8HP adapter plate
• Engine brackets
• Transmission mount
• 3.5" Aluminium driveshaft with 1350 joints and differential adapter flange.
• Oil cooler kit with banjo fittings, cooler, hoses, and fluid
• HD Aluminium Oil Pan
• Transmission controller (Turbolamik or MaxxECU).
• Shifter

Designed for a clean and bolt-on installation.

Compatibility

• Lexus GS300 (1998–2005) — first-gen fitment confirmation ongoing
• Compatible with Dodge Challenger/Charger/300C 5.7 Hemi 8HP70
• 8HP45 from V6 models can also be used (mount and flange differ)

The Fitment and first prototype

To fit the 8HP45 or 8HP70 on the GS300, we recommend to bring the engine forward to help with the firewall clearance.

Then we highlighted the places where the tunnel need to be pushed.

Everything else is pretty straight forward.

We took the time to make a new exhaust because the old one is pretty bad.

Transmission control

We plan to eventually install a built 2JZ with a single-turbo setup, a new engine harness, and a MaxxECU Race. For now, the engine is still stock, and we’re using a MaxxECU Mini solely as the transmission controller. The Mini receives RPM from the factory ECU, throttle position, and the intake MAP sensor. We also added a brake-switch input and an output for the reverse lights. With these signals, we have full transmission control.

The factory ECU does not like running without a transmission, so an ATEMU unit is required to simulate the OEM transmission and keep everything happy.

Once we switch to the MaxxECU Race and replace the factory ECU completely, none of this will be needed.

Status & Availability

This kit is now available in pre-order in our store. Limited early units are shipping first.

Follow the Build

We will be sharing updates, install guides, and dyno testing as we continue developing the GS300 swap platform.

Stay tuned for videos and documentation.

Get Yours

Visit our store to order and join the 8HP swap community.

If you have questions or want to share your GS300 project, drop us a comment below or reach out on social media.