with the v-2 on my mustang the kit came with 3.60 pulley 6rib for 8psi
i was getting a lot of slippage as i went from 3.6-3.33 then 2.95 so i opted. for an 8-rib pulley kit and the 2.87 (2.87=14psi @ 6100 rpms and 16.5-17 psi @ 7200 rpms)
with that 2.87 pulley i was at 8psi @ 4400 rpms
mustang mag did a project were some guy put a waste gate on his vortech
he got the ysi blower dropped the pulley size down so that the blower would make max boost up top like 20 or 22 psi or so added the waste gate to bleed the boost off at like 15psi or so
the dyno chart looked like a turbos dyno chart he was hitting hit 15 or so psi mark very early in the rpms
here it is
Vortech Centrifugal Supercharger Wastegate Install - Muscle Mustangs & Fast Fords Magazine