1,700-1,800 rpm stall speed. This torque converter was designed with one purpose in mind, pulling. SunCoast initially developed this converter for the fleet customer who is on the road hot-shot driving, or pulling heavy loads. The 1057 converter is 200-300 RPMs tighter than the factory converter. This converter will not spool an aftermarket turbo very well due to the efficiency of it. Your ideal customer for this converter would be a customer that tows and hauls. In-town fuel economy could improve with this torque converter.