right now, reichard's blower pulleys are available in some different sizes, in the 6 rib version vs. the 8 rib version. i have a used reichard racing 6 rib 3.3" and 3.1" vortech blower pulley for sale. i also have a used 6 rib ati balancer for sale. on a stock cobra engine with the 3.3" blower pulley i made 12.5 psi of boost with a v-2, s-trim blower with a powerpipe and 92mm pro-m meter.1BAD281 said:All I know is that I have a 3.33" on a regualar s-trim which makes 10psi (no powerpipe). I want to step up the boost (per Chris Johnson) w/ a 3.12" pulley. I would like to use the Ultragrip which only comes in a 3.00". I'm wondering what the 3.00" is rated for.