Circle D GM 252mm Pro Series PG/350/400 Torque Converter

Circle D Specialties GM 252mm Pro Series PG/350/400 Torque Converter

The Circle D Specialties GM 252mm Pro Series PG/350/400 Torque Converter is a top-tier, custom-built racing converter designed for extreme high-horsepower street and strip vehicles running a GM Powerglide, TH350, or TH400 transmission. Featuring a versatile screw-on pilot and multiple bolt pattern options, this universal design easily adapts to early GM engines as well as modern LS and Gen-V LT platforms. The compact 252mm diameter significantly reduces rotational mass while utilizing a CNC Machined Steel Stator for maximum adjustability and dialed-in launch characteristics.

Engineered for the absolute limits of track abuse, this premium converter features a rigid billet front cover with heavy-duty anti-balloon plates on both the pump and turbine. The internal assemblies are fully furnace brazed with hand TIG welded fins for structural integrity under massive torque loads. Available with a Spragless or Mechanical Diode one-way clutch, it offers bulletproof reliability for transbrake launches. For hardcore racers who need to make track-side stator adjustments or quick internal inspections, optional Billet Steel or Billet Aluminum Bolt-Together upgrades are available.

Key Features & Upgrades

• Designed for GM Powerglide (PG), TH350, and TH400 transmissions
• Innovative screw-on pilot allows adjustability for early GM or modern LS / Gen-V LT setups
• CNC Machined Steel Stator offers maximum stall adjustability (Stall options from 3600 to 5800 RPM)
• Rigid billet front cover with multiple and custom bolt pattern options
• Integrated Anti-Balloon Plates on both the pump and turbine
• Optional Bolt-Together Upgrade: Available in Billet Steel or Billet Aluminum for easy track-side maintenance
• Spragless or Mechanical Diode one-way clutch configurations available
• Fully furnace brazed and hand TIG welded fins for maximum durability

Specifications

• Application: Extreme High-Performance Street/Strip/Race Torque Converter
• Transmission Compatibility: GM Powerglide, TH350, TH400
• Converter Diameter: 252mm
• Construction: Billet Front Cover, Furnace Brazed, Hand TIG Welded
• Stator: CNC Machined Steel
• Options: Bolt-Together Housing, Midplate Spacing adjustability, and custom input shaft compatibility

Notes

• Custom manufactured product built specifically to your build's exact specifications.
• Estimated lead time: 6 weeks.