Any torque converter will provide a range of stall speed based on the load it is subjected to. The less low-speed torque that is produced, the more rear gear ratio that is used, the shorter the rear tire height, and/or the lighter the vehicle then the lower the footbrake and flash stall speed will be for a given combination. Also keep in mind that footbrake stall speed is not the actual stall speed of the torque converter, and cannot be used as an accurate gauge to determine converter performance.
You can ship your converter to our facility for a stall speed adjustment if you like. It will be far less costly than purchasing a new torque converter, and will be significantly higher quality.