Assuming your corvair has the symptoms Bob describes, park it til it's fixed? I've been told it's a throwout bearing, but I would, of course, defer to Bob's advice. Connie Iowa 65 Corsa "If it's a bad flywheel you should hear the rattle. Then, put your foot on the clutch pedal and push it in. The rattle should stop if it's the flywheel. Regards, Bob Helt"