Danno,
My 2511 has a CNC master for the clutch. Installed by PPC in Denver (Dennis Quella). The longer throw device is the slave, not the master. I have the 7/8" CNC, there is a look alike 1" also. They may look nicer but just do the same job. You can find the CNC units at most of the vendors - I do not know if the bore size difference is of importance. My 7/8" unit is used in conjunction with Dennis' internal hydraulic throwout bearing and is perhaps best suited for that application and not the stock external slave - you'd have to ask Dennis.I believe at one time replacement masters were hard to find, and the CNC filled the bill. You now should have no trouble getting a stock master replacement, though. The longer throw slave involves a smaller bore which provides the longer throw. The source for these is also the vendors.
Larry