GM Turbo 400 12" Torque Converter 2200-2600 Stall 1965-1991 TH400, 11.5" bolt circle, non lock up This Assault Racing torque converter works great in performance street / strip modified small and big block engines with a stall speed of approximately 2200 to 2600 RPM depending on application. Converter is approx. 12" in diameter with a 11.5" flexplate bolt pattern. Welded not Furnace Brazed. Contrary to popular belief, furnace brazing is not the best way to adhere torque converter components to together. Just like a Teflon coated pan, after some time the furnace brazing will erode away and ruin the stators and all other rotating parts in your transmission. Industrial Bearings - No Light Duty Needle Bearings. Needle bearings are good, but not great. Industrial bearings give these converters the ability to handle not hundreds, but thousands of pounds of torque. Thatâ€TMs much better then the higher priced alternative converters. Aircraft Aluminum Washers - NO FIBER. Assault converters utilize an aircraft quality aluminum washer instead of those old fiber washers that other companies use. This allows for more horsepower and torque capabilities. NO Automation - ALL HAND BUILT. Assault torque converters are hand built and tested to ensure that you are getting the best converter money can buy. No automated process can ensure that you will get that kind of quality. Made here in the USA.