I have updated my Blower RPM Calculator to include several differnt blower step-up ratios. Also, it will show you all of them at once. You can also use a custom step up ratio in case yours is not listed.
-Corey
http://www.slugbitchracing.com/Blower.Speed.xls
UPDATE!!!
Version 2 now addes multiple colums so you can compare differnt blower pulley sizes.
http://www.slugbitchracing.com/Blower.Speed.v2.xls