I bought a used ball from ebay that had a Vise IT system installed and it still has the molly in the bottom of the thumb installed. I plan on keeping the same layout, but changing to a Switch Grip. My question is, to install the outer sleeve for the Switch Grip will I need to go through the whole process of removing the molly, plugging the hole then redrilling to install the outer sleeve or can I just remove the molly and install the outer? (the hole is already 1 1/2")

If the hole is already 1-1/2" then the ball was originally a SwitchGrip ball that got converted to the IT. The IT system comes in 2 sizes and the drilled holes for those are 1-5/16 and 1-7/16 so if you already have 1-1/2" then it was drilled for Switch Grip initially.

I would remove the moly  and then test the hole depth with the ball on the drill press and the 1-1/2 bit.

Also chances are good that the pitches in the new ball are not the same as your's so you may need to pour the hole up to the top anyway (not a full blown plug job but....)

My pitches are 0, 0 anyway so hopefully it'll match up and save some work and $, but I'll see when I get it to the shop. Thanks everyone for their input!

thanks raider...I did not know that!!!!!

I do have a bag of the SG to IT adapter rings, however.....