How much much boost difference should 8# pulley vereses 6#with chip. single blade throttle body already installed or should i even think of running an 8 #er or would it be better to change supercharger pulley and what size is next step up from stock???? All vendors should be uniform on size of pulleys although i have heard some wre selling some as 6# that were no more than 4#'s thanks

 

1.2lb difference.
2.There is the chance your belt may slip more if you get a smaller upper pulley.
3.You want want to step down from stock. A step up would result in less boost.
4.In a perfect world all pullies would measure the same. However, it is not and all pullies, even some from the same vendor are different sizes.

Hope this helped you.