Is this what I need for more boost?

[BlueOvalStangGT]

I couldnt get my blower to boost past 5 so i think I got some gigantic pulley on it instead of stock so I was wondering if this is the one i need?

http://superchargersonline.com/product_detail.asp?PartNumber=V2A038-312

Im in france so i cqnt get a exact measurement but it was bigger then 3.5 inches so i figure its a downgraded pulley. Im in france and its hard as hell to type anything/read anything but ill post a pic of the bllower pulley in a sec. ANy other idea ahy im only making 5#s?

 

[BlueOvalStangGT]

 

[89 blue lx]

i dont have a bower but that thing looks huge man

 

[1105]

yea... plus our cars take 6 rib belts unless the blower kit comes with new pullies to change it.