This is from the MagnusonProducts site showing from and rear pulleys on the drive shaft.
It sounds like people are looking for smaller pulleys on the front of the shaft.
Could a larger pulley be used on the back end of the shaft?
As I said before, the roots blower will be my winter project. Since I'll have the front end open for the blower and cooler, I want to make all the required (and desired) changes at that time.