The physical back of the cast iron block is a Cummins B series bolt pattern. The aluminum part that bolts to the back of the block that permits a Dodge bellhousing to be attached is what we call the "engine adapter" which is also known in other parts of the world as the flywheel housing.isn't the back of the cummins a sae size?
The original question was "anyone know the sae bellhousing size for a 5.9l cummins in a dodge 2500?"You didn't get your question answered.................
The 6 BT Cummins will allow you to use either an SAE #1 (15.5" clutch) or SAE #2 (14" clutch) or any number of after market adapters that bolt up to the back of the Cummins engine block.
You can find 13 different transmissions adapters for Cummins at http://www.destroked.com/parts.shtml
and you can see a SAE #2 installed on a Dodge 3500 at http://www.sanco-bg.com/Installed Flywheel Cover_small.JPG.
Flywhell housing part numbers are found at http://www.sanco-bg.com/NV5600_Conversion_parts_list.htm