Reply to "pilot bushing and throw out bearing"

Quite right. 20 years ago I posted a suggestion that for GM type straight-finger diaphragm clutches, a radiused-face throwout bearing worked more progressively than a flat-face bearing used for stock Pantera 3-finger clutches. The tip came from Mac Tilton who has built a few racing clutches in his day.

That tip has been picked up, mis-quoted and misunderstood by many, and seems to have a life of its own, far removed from the original intent.
Once and for all: STRAIGHT FINGER diaphragm clutches such as GM sold on its '70-80s cars should use a radiused-face throwout bearing- which was what GM sold with those pressure plates. The sharp angle the straight fingers make with a flat bearing face like the Pantera uses as-stock causes a jerky feel or 'catch' at the clutch pedal as it is pushed in or released.

THIS DOES NOT APPLY TO CENTERFORCE DIAPHRAGM clutches which use bent-finger levers to fix this very problem!