Wiper Motor Helop Needed

I have a couple of wiper motors out of b bodies in real good condition and wanted to pick the best one for my 70 road runner. I have both 2 & 3 speed motors.
-What is the best way to bench test the motors, connect 12volts / ?amps to what leads?
-Is there a difference in the wiper arm connectors to the motor pivot arm of a 2 or 3 speed.
Thanks in Advance

The drive arm is different between them,and do not interchange, the shaft is much larger on the three speed motor.
The best way to check them that I have read is to plug it in the bulkhead connector and ground the motor and hit the switch...