In general, cam gears allow you to pick up a few more horses by allowing you to dial in the cam timing. Adjusting them is something that needs to be done on a dyno. However, on a JRSC they are impractical because of the lack of access to them (pulley plate is in the way). You would have to take apart quite a bit just to adjust them, put them back together, run it on the dyno, and then tear it all apart again to adjust them again, and then run it on the dyno again.... Or you could have fashioned some sort of custom pulley plate that has a series of holes in it so you could access the gears. Here is a thread where the idea was discussed quite a bit:
the JRSC pulley support bracket and cam gears......