B&M Econo 10, Inch 3500-Plus Stall Torque Converter GM Powerglide, 10.75, Inch Bolt Circle, Each (BM400010)BM400010 POWERGLIDE CONVERTER,3500 4000 Suit GM Powerglide & Trimatic, 3500 4000 rpm Part Number: BM400010 These Converters are budget priced and are intended for mild street engines up to 350 horsepower. They should not be used with nitrous, superchargers or transbrake but are perfect for street cars and hotrods. Stall speeds are based on an engine producing 230lb ft of torque at 2500 RPM. Engines with more torque will stall higher and less torque