68 383 with 750 carb. Runs rich

I can't really tell from the pics, but as far as the oil leak is concerned, make sure that the valve cover lips aren't touching the intake manifold. In many cases, at least on small blocks, cast valve covers and/or the intake port tops need to be relieved to avoid contact.

Put the valve covers on a flat surface and check for "rock" or spaces to see if they may be warped.