As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT STATED HE WAS IN NORMAL CRUISE, WHEN HE SUDDENLY LOST POWER AND NOTICED A VIBRATION FROM THE LT ENGINE. HE IMMEDIATELY FEATHERED THE LT ENGINE AND LANDED. INSP REVEALED THE NR 2 CYL EXHAUST ROCKER WAS SHEARED DUE TO A SUSPECTED CASTING DEFECT.