Circle D GM 230mm Pro Series PG/350/400 Torque Converter

Circle D Specialties GM 230mm Pro Series PG/350/400 Torque Converter

The Circle D Specialties GM 230mm Pro Series PG/350/400 Torque Converter is an elite, custom-built racing converter designed for extreme high-horsepower drag vehicles running a GM Powerglide, TH350, or TH400 transmission. The ultra-compact 230mm (approx. 9-inch) diameter drastically minimizes rotational mass to deliver explosive throttle response and enables extremely high stall speed options ranging from 4,000 up to 6,500+ RPM. Built specifically to dominate at the track, it features heavy-duty steel stator options with roller bearings on both sides for maximum efficiency and perfectly dialed-in launch characteristics.

Engineered to survive the absolute limits of drag racing abuse, this premium converter is equipped with a CNC-machined billet steel drive cover, billet steel pump and turbine hubs, and a dedicated anti-ballooning plate to completely eliminate expansion under massive power. The internal assemblies are fully furnace brazed with hand TIG welding reinforcement on the impeller and turbine fins in high-stress areas. Featuring a custom heavy-duty deep groove ball bearing turbine support and a billet steel spragless insert, it ensures bulletproof reliability during hardcore transbrake launches. For racers requiring ultimate adjustability, an optional Bolt-Together Upgrade is also available.

Key Features & Upgrades

• Designed specifically for GM Powerglide (PG), TH350, and TH400 transmissions
• Ultra-compact 230mm diameter allows for extreme 4,000 - 6,500+ RPM stall speeds
• CNC-machined billet steel drive cover and billet steel pump/turbine hubs
• Integrated anti-ballooning plate completely prevents flexing and expansion under load
• Fully furnace brazed internals with TIG welding reinforcement on fins in high-stress areas
• Heavy-duty steel stator options with roller bearings on both sides
• Custom HD deep groove ball bearing turbine support
• Billet steel spragless insert for ultimate transbrake launch reliability
• Optional Bolt-Together Upgrade: Available for easy track-side maintenance and tuning
• Optional Billet Flexplate: Available in 6-Bolt or 8-Bolt Crank Flange for LS/Gen-V LT Engines

Specifications

• Application: Extreme High-Performance Drag Racing/Strip Torque Converter
• Transmission Compatibility: GM Powerglide, TH350, TH400
• Converter Diameter: 230mm
• Construction: Billet Steel Drive Cover, Anti-Ballooning Plate, Furnace Brazed, TIG Welded Fins
• Stator: Heavy Duty Steel
• Options: Sprag Option, Bolt-Together Upgrade, Multiple Bolt Patterns, Billet Flexplate

Notes

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