Decreasing the size of your S/C pulley will increase your boost. It can also cause significant engine damage if you do not address fuel and timing issues that will occur as a result of the increased boost. You have been warned!!

I have contacted Whipple industries and they have available various sized S/C pulleys. Below is the response I got from them:

"we sell pulley from 2 1/8" -4 3/4" in ever 1/8" increment"
Richard Ruis (richard@whipplesuperchargers.com)

To contact Whipple:
Phone
(559) 442-1261

Fax
(559) 442-4153

E-mail
Technical Department: tech@whipplesuperchargers.com
Sales: sales@whipplesuperchargers.com
Webmaster: webmaster@whipplesuperchargers.com

Address
3292 N. Weber
Fresno, CA 93722

Stock (U3) pulley on the left (80mm).
"Whipple" (69.85mm--2-3/4") on the right.
Minimum belt length to use this pulley is 44-1/2".