I know one of the differences is the size of the cut out for the front or rear main. The 360 has a larger cut out. I think it's the rear. Some one will post which one. What are you up to?
A 318 pan takes the same end seal for front and rear, the 360 doesn't. I can post some pictures in a bit, but give me about 20-30 minutes as I'm downloading over 300 pictures from the car show that I went to today.
The easiest way to ID a 360 pan it has a unique end for the rear main seal gasket which is smaller than the others.
Here's the end with the unique gasket for the 360 which has the rib around the gasket seal radius. If you see this rib, then it is a dead give away that it is for a 360 only:
If you need more detailed information on identifying a SB Mopar oil pan, refer to my thread that I just made on how to ID a SB Mopar oil pan from 60's to the 80's: