Every California Performance Transmission "Mega" torque converter features furnace-brazed turbine fins (left) and a whole lot more. Without this feature, the fins will bend and distort under continued high-performance use. Art Carr and C.P.T. has converter combinations and sizes (9-, 10-, 12-inch) to go with the 200R4 for the best performance levels. Stall speeds available range from 1,800 to 4,000 rpm.