Circle D GM 265mm Pro Series PG/350/400 Torque Converter

Circle D Specialties GM 265mm Pro Series PG/350/400 Torque Converter

The Circle D Specialties GM 265mm Pro Series PG/350/400 Torque Converter is a highly versatile, high-performance upgrade for heavily modified street and strip vehicles equipped with a GM Powerglide, TH350, or TH400 transmission. The 265mm (10.5-inch) diameter offers a perfect middle ground—significantly reducing rotational mass for rapid throttle response and quick acceleration, while maintaining slightly more surface area than our smaller options for excellent streetability and efficient torque transfer.  

Engineered to handle serious power and heavy track abuse, this Pro Series converter features a rigid billet steel front cover and billet piston to eliminate flexing under load. Internally, it utilizes a flanged impeller hub for superior anti-flex durability and a deep groove ball bearing design to maximize clutch life. For builders planning to use aggressive power adders like heavy nitrous or high boost, an optional Heavy Duty Upgrade is available, which adds essential additional balloon plating on the impeller along with heavy-duty welding to ensure bulletproof reliability under extreme stress.

Key Features & Upgrades

• Designed for GM Powerglide (PG), TH350, and TH400 transmissions
• 265mm (10.5") diameter provides a superior balance of rapid engine response and streetable torque holding
• Rigid one-piece billet front cover and billet piston prevent flexing and ballooning
• Optional Heavy Duty Upgrade: Adds additional impeller balloon plating and heavy-duty welding for high-boost/nitrous applications
• Deep groove ball bearing design significantly extends clutch life
• Flanged impeller hub engineered for anti-flex durability
• Fully furnace brazed internals with hand TIG welded construction
• Hand-assembled to exacting tolerances for reliable, dominant track performance

Specifications

• Application: High-Performance Street/Strip Torque Converter
• Transmission Compatibility: GM Powerglide, TH350, TH400
• Converter Diameter: 265mm (10 1/2")
• Construction: Billet Front Cover, Furnace Brazed, Hand TIG Welded
• Bearings: Heavy-Duty Torrington Bearings & Deep Groove Ball Bearing
• Options: Multiple Stall Speeds, Sprag Options, and Heavy Duty Upgrade available

Notes

• Custom manufactured product built to your exact specifications.
• Estimated lead time: 3-4 weeks.