Cant help with the pulley size BUT.......
before mod,......sorry so late, I just got a diffirent computer
after:
The left box reads, vaccum cap here and the right box reads, "T" into here...... note that you will not be using the vTv with the little "A/B"canister in between the vac lines. I just looped it to itself on the vTv for switching back if I ever intended to.