Yes its an SCI JS pulley. I am running about 17-18lbs of boost and it probably is too much boost for an entirely stock long block.
To get the stock belt on i have to spin the blower and JS and push 1 rib on at a time. I didnt think it was slipping but there is black dust all over underneath the blower. The belt is 2 years old so I was going to repalce it, and was just getting a feel if anyone else had problems or what they were running.
I will put the blower back on tonite, install the belt and take pic of the tensioner position and see what you think.