How do you seal your small block oil pan?
I use solicone around the rubber gaskets.
Then gaskacinch on both sides of the long flat gaskets.
And some silicone in the corners and where the flat gaskets overlap the rubber end seals on the pan...
I would look more closely at your pan, the sealing flange/bead on it looks a little off (at an angle) maybe try to pound it back straight with a hammer.
You want the pan to sit flat on the block. Test it on a flat surface (table/floor) to see if it sits flat or not, then adjust as necessary.