5.0 EFI manifold question

I came across(at a junkyard)an older,Im guessing,5.0 upper intake manifold.Im never seen one like this one.I was wondering if someone here could give me little info on it.The decription goes like this:basic 5.0 manifold except the vauum ports appear to be on the top-side and thiere is 2 throttlebodies.On top it reads 5.0 EFI.It looks like it would bolt on to the 87-93 types.Is this any better than the stock ones and whats up w/the twin throttlebodies.Any input is appreicated.