Can it be changed?

I'm not sure if this where I need to ask this but here it goes. I have a 68 barracuda and I needed a wiper linkage assembly. So I bought an assembly in carlisle not thinking about if it was for a two or three speed set up. Turns out, it was for a three speed wiper set up. So...my question is can a two speed wiper set up be converted to a three speed wiper set up? Has anyone ever done this and if so, what did you have to do? Thank you for your help.

You have to change the motor, switch and wiring all at the same time to change over.