Is it possible to change the gears in a Calcutta 100b?  I have one I use on my worm rod, I think it is like 5.1:1.  Is it possible to change this to 6.3:1 or so?  

Just throwing this out and wondering if this is possible?  If it is possible what kind of money am i looking at?

Unless you found some custom gears you can't do it.  The reel is a 5.8:1 and really isn't too far off from a 6.2:1.  If you're looking for a good baitcaster that's a better ratio you may look at a shimano curado 200DHSV.  I prefer low profile reels over round baitcasters

Being a reel with no other speed version in the same size I don 't think you can change the speed, it 's not like the old Curado 200 that had 3 different speed versions or the old TDZ with 2 speed versions, you could change the speed in those by changing a couple of gears.