Is it missing a spacer or perhaps disc turned backwards causing contact between flywheel bolt heads and disc springs. You can see in pics. 11" clutch out of a COE. PO said no clutch noise, but I don't think it had been driven much in a very long time.
Yes six bolts in flywheel, had just removed one before remembering to snap a pic.
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com