What was found
APPROXIMATELY 5 MINUTES AFTER TAKEOFF FROM ST MARY'S COUNTY, MD (2W6) EN ROUTE TO CLARKSBURG, WV (KCKB), THE PILOT NOTICED AN UNUSUAL SOUND COMING FROM THE LEFT ENGINE. THE PILOT THEN NOTICED THE LEFT MANIFOLD PRESSURE BEGIN TO DROP TO APPROXIMATELY 28 INCHES AND STOP. AFTER NO FURTHER DROP OCCURRED AND NOTHING WAS OBSERVED VISUALLY FROM THE ENGINE THE PILOT SUSPECTED A PROBLEM WITH TURBO. THIS WAS FURTHER EVIDENCED BY A SLIGHT DROP OF MANIFOLD PRESSURE WHILE CONTINUING TO CLIMB. THE PILOT LEVELED AT 5000 FEET CONTACTED ATC, DESCRIBED THE PROBLEM, REQUESTED AND WAS GRANTED A PRECAUTIONARY LANDING AT EASTON, MD. MAINTENANCE ON THE FIELD FOUND A LARGE HOLE IN THE REAR CYLINDER EXHAUST STACK. THE AIRPLANE HA