Product Description:
Hawks Motorsports offers our clients this 1997-2014 Camaro Firebird GTO Corvette CTS-V LS1 LS2 LS3 LS6 Sinister Stage 2 Clutch Kit with Billet Steel Flywheel, Part #HM-25-931HD for compatible GM LS-powered manual-transmission applications using a six-bolt crankshaft and 1-1/8-inch, 26-spline transmission input shaft.
Designed for performance street and street/strip use, this single-disc clutch system provides increased holding capacity while maintaining manageable pedal effort. The 12-inch diaphragm-style pressure plate produces approximately 2,800 pounds of clamping force and offers increased surface area for heat dissipation.
The six-paddle clutch disc uses sintered-bronze friction material for increased torque capacity. Its sprung center hub provides additional dampening to help control driveline shock during engagement. The package is rated for applications producing up to 650 horsepower.
A precision-balanced, surface-ground billet steel flywheel completes the system, providing a stable mating surface for consistent clutch engagement. This is a new aftermarket performance kit rather than an original-equipment or restoration-style replacement.
Key Features:
- Brand: Sinister by Hawks Motorsports
- Hawks Motorsports part number: HM-25-931HD
- Component-system number: 25-931HD
- Product type: Single-disc performance clutch and flywheel kit
- Recommended use: Performance street and street/strip
- Advertised capacity: Up to 650 horsepower
- Clutch diameter: 12 inches
- Input-shaft size: 1-1/8 inches
- Input-shaft spline count: 26
- Pressure-plate design: Diaphragm
- Pressure-plate clamping force: Approximately 2,800 pounds
- Clutch-disc design: Six-paddle metallic disc
- Friction material: Sintered bronze
- Hub type: Sprung hub
- Flywheel material: Billet steel
- Flywheel weight: Approximately 28 pounds
- Crankshaft mounting pattern: Six-bolt GM LS
- Flywheel preparation: Precision balanced and surface ground
- Finish or color: Not consistently specified
- Vehicle location: Between the engine and manual transmission
- Side designation: Not applicable
- Quantity: One complete clutch-and-flywheel package
- Application type: New aftermarket performance upgrade
- Country of manufacture: USA
Kit contents:
- One billet steel six-bolt flywheel
- One 12-inch diaphragm pressure plate
- One 12-inch six-paddle clutch disc
- One pressure-plate bolt set
- Pressure-plate dowel pins
- One clutch alignment tool
- One slave-cylinder spacer
Fitment Applications:
This kit is designed for compatible manual-transmission vehicles equipped with an LS1, LS2, LS3, or LS6 engine, six-bolt crankshaft, and 1-1/8-inch, 26-spline input shaft.
Verified or supported vehicle families include:
- 1998-2002 Chevrolet Camaro Z28 with LS1 and compatible manual transmission
- 1998-2002 Chevrolet Camaro SS with LS1 and compatible manual transmission
- 1998-2002 Pontiac Firebird Formula with LS1 and compatible manual transmission
- 1998-2002 Pontiac Firebird Trans Am with LS1 and compatible manual transmission
- 1998-2002 Pontiac Firebird Trans Am WS6 with LS1 and compatible manual transmission
- 2004 Pontiac GTO with LS1 and compatible manual transmission
- 2005-2006 Pontiac GTO with LS2 and compatible manual transmission
- 1997-2000 Chevrolet Corvette with LS1 and compatible manual transmission
- 2001-2004 Chevrolet Corvette with LS1 or LS6 and compatible manual transmission
- 2005-2007 Chevrolet Corvette with LS2 and compatible manual transmission
- 2008-2013 Chevrolet Corvette with LS3 and compatible manual transmission
- 2004-2005 Cadillac CTS-V with LS6 and compatible manual transmission
- 2006-2007 Cadillac CTS-V with LS2 and compatible manual transmission
- 2010-2014 Chevrolet Camaro SS with LS3 and compatible manual transmission
The advertised 1997-2014 range represents the combined model-year coverage across the listed vehicle families. It does not mean this kit fits every Camaro, Firebird, GTO, Corvette, or CTS-V manufactured during those years.
Known exclusions:
- Does not fit V6 Camaro or Firebird applications
- Does not fit automatic-transmission vehicles
- Does not fit 1997 Camaro or Firebird models with the LT1 engine
- Does not fit LS applications using an eight-bolt crankshaft
- Does not fit Corvette ZR1 models using the LS9 nine-bolt crankshaft
- LS7, LS9, LSA, and LT-series applications are not included in the stated HM-25-931HD engine fitment
- Does not fit 2009-2014 CTS-V models with the LSA engine
- Does not fit 2010-2014 Camaro V6 models
- Does not fit 2012-2014 Camaro ZL1 models
- Does not fit the 2014 Corvette Stingray LT1 application
- Does not fit transmissions with an input-shaft diameter or spline count other than 1-1/8-inch, 26-spline
- Modified engine-swap applications require additional dimensional and hydraulic verification
No verified GM interchange number applies because this is a multi-component aftermarket performance system.
Installation Notes:
Professional installation is strongly recommended. Verify the engine code, crankshaft bolt pattern, transmission input-shaft size, spline count, bellhousing configuration, hydraulic release system, and available clutch clearance before ordering.
This kit requires a compatible six-bolt GM LS crankshaft and 1-1/8-inch, 26-spline transmission input shaft. Do not order by vehicle year alone.
Inspect the rear main seal, pilot bearing, hydraulic release bearing/slave cylinder, clutch master cylinder, and transmission input shaft before installation. Replacement or upgraded hydraulic components are recommended when their condition or operating range is questionable.
Use the included slave-cylinder spacer only when required by the measured release-bearing clearance. Hydraulic release-bearing clearance must be measured after the clutch and flywheel are installed. Incorrect clearance or spacer selection can cause incomplete release, clutch slippage, premature bearing failure, or pressure-plate damage.
The flywheel must be thoroughly cleaned before installation. Check flywheel runout, bellhousing alignment, clutch-disc orientation, starter engagement, and pressure-plate seating. Follow the applicable manufacturer specifications for fastener preparation, tightening sequence, and torque.
The pressure-plate bolts are included. Crankshaft-to-flywheel bolts are not listed as included. A compatible six-bolt flywheel bolt set must be purchased separately.
A replacement hydraulic release bearing/slave cylinder, pilot bearing, clutch master cylinder, flywheel bolts, bellhousing hardware, transmission fluid, and installation fluids are not included unless specifically shown or stated at the time of purchase.
The Hawks listing identifies a slave spacer as included, while the component manufacturer’s current contents list identifies an alignment tool but does not mention the spacer. Confirm current package contents before ordering.
The manufacturer currently uses both “700HP” in the product title and “up to 650 HP” in its technical specifications. Hawks Motorsports rates this Stage 2 package at up to 650 horsepower; actual clutch capacity depends on vehicle weight, torque output, gearing, tire traction, driving style, and intended use.
Verify before ordering.
