[cleszkie]

Have you considered getting rid of the Centerforce pressure plate for something a little softer? Seems you are stressing the stock linkage beyond what it was designed for with that stiiff plate. You state that you have a very worked 350, so you shouldn't need all the grab that the Centerforce is providing. If you do keep the Centerforce, I would consider replacing the old linkage with a hydraullic slave cylinder and never look back. You would have a nice easy pedal with the stiffest pressure plate you could throw in there.