I installed a rebuilt 261 2 years ago and have since had an issue with the clutch . I used the same flywheel which I had machined flat , 11 in. clutch disk and pressure
plate off the original 235 which never had any issues . But since the transplant whenever I depress the clutch to its full extent it lack of a better term it chatters and rumbles , but only when totally depressed . I've replaced the throw out bearing twice and noticed that the tips of the fingers on the diaphragm are a bit warn as the paint is missing .
BUT upon checking the pilot bushing with a spare input shaft that's around 6 in. long the shaft will wobble side to side about 2 inches .
I then removed the pilot bushing and upon inspection it seems the center hole is oval . I have since replaced the bushing and the shaft is now tighter .
Could the pilot bushing have been the cause or should I look elsewhere ??? I'm guessing the bushing was not replaced when the engine was rebuilt .

John

good planning is no substitute for dumb luck