About this product
Universal Quick Change Weld-In Kit
The FDF Universal Quick Change Weld-In Kit makes mounting a quick change differential in your chassis a lot easier. The weld-in plates locate the diff for you and add strength and rigidity to your subframe, so you aren't starting from scratch or guessing at measurements.
It's also a great starting point for custom chassis and one-off projects. Buy the digital cut files and modify them to suit your build. The critical dimensions and the thought process behind them are already done for you, so you can change the box to fit your car without worrying about where the diff ends up.
The tab-and-slot design lets everything key together and line up before you weld. Compatible with Winters, Bull Dog and Speedtek quick change differentials.
Pick How You Want It
- Digital Cut Files: The full set of files to modify and cut yourself. All the critical diff mounting dimensions are built in.
- Physical Cut Parts: Laser cut plates from our shop, ready to tack together and weld.
- Welded Quick Change Box: We weld the box together for you. It shows up ready to drop in and mount to your chassis.
Specs
- Material: 3/16" high strength steel plate.
- Digital Cut Files: Supplied as .dxf files, ready for laser, plasma or waterjet cutting.
- Hardware: Mounting hardware is included with the Physical Cut Parts and the Welded Quick Change Box.
- Lead time: Physical Cut Parts and the Welded Quick Change Box ship in 1 to 2 weeks.
Key Features:
- Universal design: Suits a wide range of chassis, custom builds and unique projects.
- Critical dimensions done for you: Modify the outside of the box all you want, the diff mounting stays right.
- Tab-and-slot construction: Easy assembly and alignment before welding.
- Stronger subframe: Reinforces your existing subframe and adds rigidity.
- Diff compatibility: Works with Winters, Bull Dog and Speedtek quick change differentials.
Note: Custom fabrication and additional reinforcement may be required depending on your chassis. Speedtek differentials require metric mounting hardware.
Why Choose FDF?
- Driver-inspired designs: Our products feature innovative, driver-inspired designs tailored for performance and style.
- High-quality materials: We use only high-strength alloys to ensure the durability and superior quality of our products.
- Made in North America: Our products are proudly made in-house in North America, ensuring exceptional craftsmanship and reliability.
Description supplied by FDFRaceshop through its current Shopify listing. Product, performance, and health claims are the seller’s and have not been independently verified by StorkScout.

