Transmission & Drivetrain

Handling the Horsepower: Transmission and Drivetrain Components for Pontiacs at Butler Performance

1. Automatic Transmission Components: Flexplates and Converters

For automatic-equipped Pontiacs, the reliability of the torque converter and the flexplate is paramount.

• Flexplates (Automatic): The flexplate bolts to the back of the crankshaft and connects the engine to the torque converter.¹ For high-horsepower engines, a heavy-duty, SFI-certified flexplate is mandatory. These units are significantly stronger than stock, designed to withstand the engine's torque and the rigors of high-RPM launches without cracking or warping. SFI certification is often required for racing to ensure safety.

   

   

• Torque Converters: This component multiplies torque at launch and is essential for matching the engine's power band (especially the camshaft) to the vehicle's weight.³ Butler Performance offers:

    

  • Performance Converters: Available in various stall speeds (e.g., $2,500 \text{ to } 4,500 \text{ RPM}$) to allow the engine to flash up into its peak torque range upon launch, maximizing acceleration.

  • Brand Name Quality: Converters are sourced from top manufacturers like B&M, Hughes, or TCI, ensuring consistent quality and performance.

2. Manual Transmission Components: Flywheels and Clutches

For those who prefer the engagement of a manual transmission, Butler Performance supplies components to handle serious horsepower while maintaining a smooth shift feel.

• Flywheels (Manual): Like the flexplate, the flywheel must be strong and often SFI-certified. Performance flywheels are available in steel or lightweight aluminum, offering builders a choice between enhanced durability and quicker engine response (reduced rotational inertia).⁴

   

   

• Clutches: The clutch must be able to hold the engine’s torque without slipping.⁵ Butler stocks complete clutch kits with various pressure plate and friction material options:⁶

   
   

   

  • Heavy-Duty Street Clutches: Designed for performance use while retaining street manners and acceptable pedal effort.

  • Multi-Disc Clutches: For extreme horsepower applications, multi-disc clutches offer massive clamping force and holding power in a manageable package.

3. Complete Transmissions and Related Components

Butler Performance recognizes the need for complete transmission solutions that can handle the increased power output.

• Transmissions: While not always built in-house, Butler provides access to reinforced automatic transmissions (like the Turbo 400 or 200-4R)⁷ or high-end manual transmissions (like the Tremec TKO or Magnum). These units are internally upgraded with heavy-duty clutches, bands, and shafts to prevent failure.

   

   

• Bellhousings: SFI-approved steel or aluminum bellhousings are essential for safety in racing applications, designed to contain clutch or flywheel shrapnel in the event of a failure.

• Hydraulic Clutch Kits: For modernizing classic Pontiacs, hydraulic clutch conversion kits offer smoother, more consistent pedal feel and often simplify firewall clearance compared to old mechanical linkage setups.⁸

   

   

4. Drivetrain Accessories

The final connections between the transmission and the rear axle are addressed with key accessories:

• Transmission Components: This includes necessary seals, gaskets, torque arm reinforcements, and shifter kits to complete the transmission swap or upgrade.

By offering these critical, high-strength transmission and drivetrain components, Butler Performance ensures that every horsepower generated by their engine is effectively and reliably translated into tire-shredding performance on the street or the strip.