Oil dripping from the torque converter shield.
 

Does the Detroit have a rear main seal like the small block 350?

Yes and it is a one piece seal.

Also be aware that there is a valley drain that exits down the back of the block and will drip from ther bell housing cover-any fuel leaks from above will appear the same as a rear main leak.

You might be correct...again. Starting to notice a pattern with you racer.

I just changed the fuel filter housing and fuel bleed work. It might be some residual diesel.

Yep, the leak lessened until non existent. Thanks!