No matter what the torque is you need to know what RPM it peaks at. If it peaks at 4200, get a convertor that locks up around 3500. Don't be fooled into a convertor that locks up at 4500 or higher, why have a convertor locking up after your torque has already peaked, has dropped and it still dropping. Torque is what accelerates weight, you want your convertor locked up before the peak torque RPM to take advantage of the highest torque moving your car forward.