James,
Is one of the threaded holes for the pressure-plate attachment screws stripped? Usually a stripped hole is missing some of the parent metal and retapping it would result in imperfect threads. A threaded insert (Keensert) could be installed to provide a good thread. Aluminum flywheels use steel inserts.
I am using a Howe hydraulic throwout bearing with my 261. Seems to work just fine.
