Just to clarify to those who emailed me privately,
The Shelby external slave cylinder does work and it is very simple to setup. The bellhousing does not need to be cut for fork clearance. The pushrod from the slave still allows the fork to travel in the same arc as Ford intended. It sounds like whoever sold David the parts he used, sent him some goofball pieces. MANY,MANY Shelbys have been built and successfully use the external unit, including the 2000 and 3000 series cars from the 60's.
I know of one guy who had problems with his internal bearing:
http://www.cobralads.com/butcher37.html