Now if you look at my intake, which is a cross ram from A&A, you'll notice that the intake will seal across the top of the indexing holes but there is no way it can seal below the indexing hole as there is no material there. Since this area was not totally sealed oil was getting out of the valley and saturating the bottom of the gaskets and in my case was leaking out the rear of the valley pan rails.
I've applied silicone to the gaskets, on the head side, around each indexing hole and have slowed the leak quite a bit but I don't think it is totally fixed, still a very minor leak.
So check and make sure the intake has material where it needs to seal ALL areas.