Sounds like the input shaft isn't slowing down. Either your input shaft is bound up in the end of the crank with a stuck pilot bushing or the clutch is not disengaging. Severe mis-alignment could also do that . Dis it happen all of a sudden or did you change something?
Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60