Edelbrock Air Gap Cheap Knockoff
I have no reference orexperience with either of these manifolds for small block Mopar, tho everything I've read or seen says an rpm is the premier street manifold for just about everything.
However, just yesterday I saw a episode of engine masters testing BBC two plane manifolds on a mild 454, and the speedmaster clone/copy of the rpm airgap was down about 3hp/5ftLb to the real thing.
And yes, of course that means nothing to the comparison of sbm manifolds, I just found it interesting.