[Hammer]

Mustang Cobra Upper Plenum

I've heard others call the upper intake manifold a plenum, but I've always known them as upper and lower intake manifolds.
Don't forget that Cobras also come with an IMRC (Intake Manifold Runner Control) along with the lower intake manifold.

if i got a new manifold i could put the Cobra Upper Plenum on my gt engine

I don't think that is correct.
I've never seen a DOHC Cobra intake on a 4.6 SOHC motor before. Not saying its impossible, but I doubt it.

If you're looking for an intake\heads combo, go with the 00-02 PI heads\intake or the SVO heads\intake....