My 350 did the same thing. Flywheel nut came loose. Scared the crap out of me though.
Then of course I couldnt get the clutch bell off because it was just turning the engine when I tried to unscrew it. I bought a 'piston stop' tool at my LHS. It screws in the head where the plug usually goes and stops the piston before TDC so that you can unscrew the clutch bell.
Once the clutch bell was off all I had to do was retighten the flywheel nut with my 4-way wrench and I was good to go. Didn't have to mess with the clutch shoes or anything.