As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CYLINDER HEAD SEPARATED FROM BARREL IN FLIGHT. PILOT NOTICED ROUGH ENGINE AND MADE PRECAUTIONARY LANDING. FAILED CYLINDER WAS 'LIGHT' CASTING WHILE OTHER FIVE WERE 'HEAVY' CASTING. HEAD SEPARATION ALSO CAUSED FUEL LINE SEPARATION AND EXHAUST Y-PIPE DAMAGE. ENGINE HAD 511 HOURS SINCE OVERHAUL BY SHOP IN CANADA. POSSIBLE CAUSE OF FAILURE, INTERNAL CORROSION BETWEEN BARREL AND HEAD THREADS.