O-ring part number

[Bandit02]

Does anyone know the Cummins or equivalent part number for the oil filter adapter base o-ring? The big one. Mine is leaking, I followed the instructions to the T but it leaks so I'd like to change it.

 

[M35A2-AZ]

The number is in the 5 Ton Sticky thread. It Show to be napa 5271 or wix 15271, but that is not listed as coming with the filter.
The filter to use is a Wix 51954. Look at the Wix web site and it shows all the gaskets that come with the filter.
http://www.steelsoldiers.com/showthread.php?82404-5-ton-Parts-Quick-Reference-Spreadsheet

http://www.wixfilters.com/Lookup/Exactmatch.aspx?PartNo=1954