Clutch Masters Engine Adapter Plate for Honda K Engine to Subaru STI 6-Speed Transmission

SKU: K721-EAP

Clutch Masters Engine Adapter Plate for Honda K Engine to Subaru STI 6-Speed Transmission

The Clutch Masters Engine Adapter Plate (SKU: K721-EAP), the premier choice for seamlessly mating a Honda K-Series engine (K20/K24) to a Subaru STI 6-speed transmission. Engineered for enthusiasts and racers, this adapter plate delivers unparalleled performance, reliability, and compatibility, making it the top choice for high-horsepower K-Series swaps into Subaru platforms. Unlike other options, this kit combines cutting-edge engineering with premium materials to ensure a perfect fit, effortless installation, and exceptional durability, even under the most demanding conditions. Whether you're building a street monster or a track-dominating beast, the Clutch Masters K721-EAP is the definitive solution for your Honda K to Subaru STI swap.

Why Choose Clutch Masters? 

• Engineering: Designed with a 1-inch thick adapter plate, this kit ensures robust alignment and compatibility, supporting both single-disc and twin-disc clutch setups for power levels from mild to wild. 
• Performance: Optimized for high-horsepower applications, the K721-EAP enables smooth power transfer without sacrificing drivability, unlike competitors that compromise pedal feel or thrust bearing longevity. 
• Precision Fitment: Tailored specifically for Honda K20/K24 engines and Subaru STI 6-speed transmissions, ensuring a bolt-on solution with no guesswork. 
• Industry-Leading Innovation: Clutch Masters’ Hi-Leverage™ technology enhances clamping force without increasing pedal pressure, reducing wear on critical components like the crankshaft thrust bearing. 
• Trusted by Enthusiasts: Backed by Clutch Masters’ decades of experience in performance clutch systems, this adapter plate is the go-to choice for professional builders and DIY enthusiasts alike.

What’s Included in the Purchase? 

• Engine Adapter Plate (Part #K721-EAP): Precision-machined 1-inch thick adapter plate for mating Honda K-Series engines to Subaru STI 6-speed transmissions. 
• Starter Cover Plate: Covers the starter hole on the Subaru transmission, allowing the use of the factory Honda starter and a RWD K-Series wiring harness. 
• Complete Hardware Kit: All necessary bolts and mounting hardware for a secure and straightforward installation. 
• Optional Flywheel Compatibility: Supports single-disc flywheels (Part #FW-K721-SF) for use with OE-style Subaru STI 6-speed clutch kits or Clutch Masters FX Series clutch kits. Also compatible with twin-disc flywheels (Part #FW-K915-SF) for high-horsepower builds using Clutch Masters 850 Series twin-disc clutches (sold separately).

Vehicle Fitment 

• Honda K-Series Engines: 
  • K20 (2002-2011 Honda Civic Si, 2002-2006 Acura RSX, 2004-2008 Acura TSX) 
  • K24 (2002-2008 Honda CR-V, 2003-2011 Honda Accord, 2004-2008 Acura TSX, 2003-2007 Honda Element)
• Subaru Models with STI 6-Speed Transmission: 
  • 2004-2021 Subaru Impreza WRX STI (EJ257 engine, 6-speed manual) 
  • 2004-2007 Subaru Forester XT (with STI 6-speed swap) 
  • 2004-2008 Subaru Legacy GT (with STI 6-speed swap) 
  • Other Subaru models with EJ-series 6-speed transmission swaps (consult a professional for compatibility).

Note: This kit angles the Honda K engine at the factory 11-degree tilt to the passenger side for proper alignment. Fitment requires a compatible Subaru STI 6-speed transmission (TY856 series). Always verify transmission compatibility with your specific Subaru model year and VIN.

Key Features:

Versatile Clutch Options: Supports both OE-style Subaru STI clutch kits and Clutch Masters’ high-performance FX Series or 850 Series twin-disc clutches, catering to street, drag, or track applications. 

Hassle-Free Installation: Utilizes the factory Honda starter and includes a cover plate for the Subaru transmission, simplifying wiring and setup. 

Durable Construction: Built to withstand the rigors of high-performance driving, ensuring long-term reliability in street and motorsport environments. 

Enhanced Drivability: Clutch Masters’ advanced design minimizes pedal pressure while maximizing holding power, providing a smooth and responsive driving experience.