I've had 10psi with a
3.8" pulley and non-intercooled Vortech Si
3.6" pulley, aftercooler, and Vortech Si
3.4" pulley, intercooled, and Paxton 2200
They all made it around 6,500 rpm. Every time I needed to get the pulley off I just took the head unit to my local speed shop and they took it...