Narrative:

Flying at 12;000 ft had roughness of engine; contacted ATC requested descent to nearest large airport. Got vectored to ZZZ. At 6;000 ft low oil pressure and engine shaking badly feathered prop while still able and landed without incident at ZZZ.

Google
 

Original NASA ASRS Text

Title: C421 pilot experiences engine roughness at 12;000 FT and requests vectors to a suitable airport. At 6;000 FT low oil pressure is indicated and with the engine shaking badly it is shut down. A safe landing ensues.

Narrative: Flying at 12;000 FT had roughness of engine; contacted ATC requested descent to nearest large airport. Got vectored to ZZZ. At 6;000 FT low oil pressure and engine shaking badly feathered prop while still able and landed without incident at ZZZ.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.