A performance torque converter is highly specialized based on the performance characteristics of the specific vehicle. Sonnax has several levels of kits to ensure the best combination of performance and value for each application.

Sonnax 300mm performance converter kit GM-RK-408 for GM 4L60-E, 4L65-E, 4L75-E (300mm) applications delivers the performance characteristics of a high-stall with maximum lockup capacity. Sonnax performance converter kits ensure fast, easy assembly with predictable tuning adjustments.

Sonnax offers the most comprehensive range — and growing number — of converter kits for anyone building a GM 4L60-E, 4L65-E, 4L75-E (300mm). Other kits that utilize GM 245mm or 265mm core are available.

• Build in a variety of stall speeds
• Fast, easy assembly with predictable tuning adjustments
• Fits 10.750", 11.062" and 11.500" flexplate bolt patterns
• Chromoly steel turbine and impeller hubs for strength and durability
• Fully-machined forged front cover and damperless piston add strength and durability
• Sprag cartridge delivers more than twice the holding capacity of OE
• Weld-on pilot adapts to many applications