That pitting on the crank is easily ground down before the crank goes in. The seal has plenty of give to it to take up a light cut.

Also a speedie sleeve can be put on over the end of the crank. I have even lightly milled the seal housing to move the seal up a few thou to get the seal into a clean area. Wth a small cleanup the oil pan bolts still line up.

Also you fuel pump can leak oil, as can the little port cover at the left front of the motor for the ballance shaft. The all tend to make drips at the back since the engine has a tilt towards the back.

Kevin