KellTrac S650 Mustang IRS Bushing Upgrade Kit, Level 1 (KTI-BUK24L1) - 2024–2026 Mustang GT & Dark Horse
The KellTrac Level 1 IRS Bushing Upgrade Kit is designed for S650 Mustang owners who want to eliminate factory deflection and dramatically improve rear suspension control without sacrificing street manners. By addressing the most critical weak points in the factory IRS, this kit delivers sharper handling, improved traction, and a more connected driving experience in all performance scenarios.
This Level 1 system combines KellTrac’s proven Posi-Loc subframe solution with precision-engineered spherical lower control arm bearings and lightweight centering sleeves. Together, these components positively locate the IRS subframe and rear lower control arms, eliminating unwanted movement that causes wheel hop, inconsistent alignment, and loss of traction under load.
Engineered for spirited street driving, drag racing, road course use, and autocross, the Level 1 kit strikes the perfect balance between performance and drivability. With carefully selected materials and precision fitment, it delivers meaningful gains with only a minimal increase in NVH—making it an ideal foundation upgrade for serious S650 builds.
Features
KellTrac Posi-Loc System
- CNC-machined lightweight components
- 6061-T6 billet aluminum construction with black anodized finish
- Precision fitment for maximum subframe control
- Industry-first rear lower design replacing the factory bushing stop plate
- Zero increase in noise, vibration, or harshness
Rear Lower Control Arm Bearing Kit
- Most proven S650-specific lower control arm bearings
- Super-strong CNC-machined steel bearing bodies
- Industry-leading durable coating
- 6061-T6 billet aluminum bearing offset spacers
- 1-inch spherical bearings for precise axle location
- Minimal NVH increase, highly recommended for performance applications
Polyurethane Centering Sleeves
- Extremely lightweight, precision-molded design
- Accurately centers the IRS subframe to the chassis
- Zero increase in noise, vibration, or harshness
- Industry-unique polyurethane construction
Benefits
- Reduces wheel hop and improves traction
- Centers and positively locates the IRS subframe
- Improves handling response and overall vehicle feel
- Helps prevent premature bushing and driveline component damage
- Can assist in reducing driveline vibrations
- Reduces pinion angle change under heavy wide-open-throttle loads
- Minimizes unwanted suspension geometry and alignment changes under load
Fitment
- 2024 Ford Mustang GT
- 2024 Ford Mustang Dark Horse
- 2025 Ford Mustang GT
- 2025 Ford Mustang Dark Horse
- 2026 Ford Mustang GT
- 2026 Ford Mustang Dark Horse
Kelltrac Terms Of Service
Kelly considers his Kelltrac line to be a specialty line for a unique customer base and has his own terms of service in addition to Beefcake Racing's. You must accept these terms on all Kelltrac orders. Please read shipping times, cancellation, and returns. If time is of the essence, we do have other options that can ship right away / quicker. Just reach out to one of our sales associates at Beefcake Racing.
Cancellations & Returns
KellTrac Innovations does not accept product returns. Once your order ships, you own it and we will not accept it back - NO EXCEPTIONS. We do not accept order cancellations after the product has shipped. If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
Due to the custom nature of our business and product offerings, we charge a 20% order cancellation fee, period, non-negotiable, no matter who you are. Orders can only be cancelled before the product ships. We do not accept order cancellations after the product has shipped. If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
Leadtime
Please be aware that most orders ship within 2-4 weeks. In some (rare) cases, orders can take up to 6-8 weeks to ship. Holidays can severely impact these lead times. *DO NOT CONTACT US ABOUT YOUR ORDER UNLESS IT IS OLDER THAN 20 BUSINESS DAYS!* If you understand and accept this please check the box and continue checking out. If you do not accept this, please stop and discontinue the order process. Thanks!
CA Residents: WARNING: Cancer and Reproductive Harm www.P65Warnings.ca.gov
