Well, by GOD you got SOMETHING wrong somewhere. At this point, I would literally get a magnifying glass out and look at those valve cover rails on the heads. I have seen a couple have cracks in them before.
Well I'm thinking maybe the winged bolts aren't tight enough, so I went and got some 1/4" 20 nuts, going to install them first and torque them down, the wing nuts will go over that.