My 5.0 intake was sucking air/
oil up out of the lifter gallery. The gaskets were in good shape and look like they could be re-used (not that I would). I have checked the head and intake with a straight edge. I have checked the angle of the seal surfaces. Everything matches up and looks perfect. This has bugged me, as I do not subscribe to the $hit just happens theory of life. If it happens there is a reason.
It dawned on me that an RTV type sealant was used around the water ports, but not the intake ports. So I checked the thickness of the intake gaskets, and sure enough they are about 0.010- 0.015" thinker at the water ports. I suspect the extra thickness held the intake up and left a slight gap at the intake ports. I do not think this is a good practice. I'm fairly certain this was what caused my leak.