D6B serial number location

The location serial number is on left side rear stering cluch housing and on side motor near oil cooler and oil refell pipe.

On the left side of the engine block just under the head joint about halfway along or towards the rear, if the plate is missing and you can see the remains of the rivets or rivet holes, clean the area between them and the number is stamped in the block.

The location serial number is on left side rear stering cluch housing and on side motor near oil cooler and oil refell pipe.

On the left side of the engine block just under the head joint about halfway along or towards the rear, if the plate is missing and you can see the remains of the rivets or rivet holes, clean the area between them and the number is stamped in the block.

Thanks. I looked over this area and found tag missing and an alternate number 59 stamped in its place.

D6B's are either 37Axxxx (narrow gauge) or 44Axxxx (wide gauge) if US built. There is no 59 series D6's. There is a 59Jxxxx but that's a D4D model.
There is a 69Jxxxx D6C model with D333A engine (3-1/2" bore).
There is also a D333A industrial engine with 59Bxxxx s/n.
Your engine may have been changed as previously stated.