Considering manifolds

My L.H. stock manifold would not work with Edelbrock heads, out of the box. Had to machine off some excess material on the bottom/outside edge of the head where it interfered. You'll see where the interference is if you mock it up before trying to bolt on the manifold.

Anyways, I think you'd be better of with headers, because as good as those stock manifolds are, they were never meant to flow what a 416 cu. in. engine needs at higher RPM.