This sucks!

I can't imagine it has enough of a bulge to hit the lifter valley. There's at least 3-4" there between them. I've had several edelbrock's in the past and now have a rpm air gap and even with a lifter valley tray in my 360 it clears. Did you pull the roll pins out of the block where the end seals go? If not check that. That may be what is holding it up. If their not there set the manifold back down and scrub it back and forth a little to put marks on it where it's hitting and flip it back over and you should See where it's hitting by the scrub marks on the manifold.