As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE , CRUISING AT 13,000 FT, PILOT NOTICED RIGHT ENGINE MANIFOLD PRESSURE DECLINING AND POWER WAS REDUCING. REDUCED HIS ALTITUDE TO 7000 FT. NOTICED A VIBRATION AND OIL STREAMING FROM RIGHT ENGINE. SHUTRIGHT ENGINE DOWN AND FEATHERED PROPELLER. DECLARED AN EMERGENCY AND LANDED UNEVENTFULLY. MAINTENANCE FOUND THE TWO BOTTOM STUDS SECURING THE CYLINDER TO THE ENGINE BLOCK BROKEN OFF.