You have piqued my curiosity and I just have to ask... why are you replacing the motor? The only reason I ask is that the mid-90's Chevy and GMC pick-ups, vans and SUV's have a notorious problem with the wipers caused by a faulty circuit board. Never have I seen one of these units where the motor itself was bad - it has always been the circuit board.
If you are experiencing any of the following issues, I would repair or replace the circuit board first before replacing the motor: Wipers work intermittently or stop working altogether, occasionally in mid-stroke. Mist and/or washer function eratic or not functioning. Delay feature not functioning or speed is the same regardless of delay setting. Delay feature notably faster on all settings than usual. High or Low speed not functioning or eratic. Wipers may work if you tap on the motor housing or wiggle the wiring harness connector.
There is a recall for this problem and you can search on
Good luck - Jonathan