If you are doing a conversion on a 70-71 E-Body or a 71-74 B-Body from a 2-spd. to a 3 or variable spd. motor, you will have to replace the wiper motor crank with part #2822289-(70-71), also the link from the motor to the driver's side pivot with part #2822293(70-71)or crank with part #3431518 and link #3431102 (72-74). You will need a variable speed switch ending with part number 3488380 (1970-71 Application: B,J CV, L Dash SW Bezel,PU2947792SOP,Ribbed) or part #3488380A (1970-71, Application: 1970-71 B,J CV, L Dash SW Bezel,PU3488406SOP,Smooth).

If you are doing a 2 to 3 speed conversion on a 68-70 B Body application, you will have to replace the wiper motor crank with part #2822273, 3 speed bushing part #2580200, and a 3 speed switch part #2864014. The rest of the linkage, wiring etc remains the same. If you find any information that you find contrary to what I have posted here, please contact me. While I'd love to say I have one of every model, I don't, these numbers, etc. have been researched and/or put into practical application and duly noted...I'm not perfect and I'm always willing to learn!