I just recently asked if anyone had any information on a N47 intake manifold that had the heat shield cast as part of the manidfold. Upon further inspection of it today I was able to see that was not a heat shield but a webbing between the manifold inlets. At this point I'm guessing this is a turbo intake manifold. Am I guessing right?

Nope, I think it was used on both the turbo and normally aspirated engines.

does anyone know if the 280z manifolds and 280zx manifold are interchangeable, and if so whats a easy method of telling the diff. between the two

If I remember correctly, the TB and plenum are much smaller on the N/A ZX.

sorry not familiar with these parts whats the TB and plenum, and do they need to be changed to do the swap?

My 77 280Z and my 79 280ZX spare motor both have N47 heads. The one on IN my car does not have the webbing and the one on the 79 motor does. Of coarse neither is turbo, so I think the webbing means its off a 280ZX unless the 78 had webbing too.

webbing is on the later manifolds (with egr?)

TB = throttle body

plenum = tubes that go from the "log" of the manifold to the ports on the head. the "fingers" of the manifold. size of plenum refers to the area and flow inside of the fingers