I bought a used Littlefield 14-71 and other blower parts off www.racingjunk.com
Am a little dissapointed about a couple things but got a really good price on on everything .
In hindsight I would buy one from WWW.rbssuperchargers.com and be sure of what I was getting. At their homepage, click on--->products then in the little box where it says "new" click on it and select "used" and search for superchargers. Plenty to pick from.
I was told not to get a magnesiem blower since the soft metal wears easily, FYI.
Be good, Jim