Hi Willy,
All Pantera standard iron heads are 4V, Blue thunder intake manifold is a 4V and Scott cook dual plane manifold is 3V but you can, as timsteren said, put Scott 3V manifold on pantera heads without problemes, I also put an Scott manifold on standard iron heads but I enlarged the passages from 3V to 4V.
Cheaper than Blue thunder an Scott intake, there are the Edelbrock performer intake manifold.
D1ZX is a 4 V aluminium square bore intake manifold (X for alu), very rare, is not a Blue thunder one.
You have to disassemble the carburetor to check if it is a Mustang D3ZE or a Pantera GTS D3ZE intake manifold, on the Pantera GTS D3ZE there are enlargements of the secondaries ducts (eggs shapped). According to George Pence (see thread: pantera.infopop.cc/topic/correct-carb-manifold-combo), these enlargements allow a square carburetor fitment (holley 4777).....! with which spacer ?. For information: On my GTS (1979), before I switch for a Scott intake, I had a D3ZE intake manifold with enlargements of the secondaries ducts equipped with an Holley 600 CFM (4160) with a strange spacer (no reference on it and never seen before) but I don't know if it's original (see photo of my spacer).
If your D3ZE manifold is a mustang one (without secondaries enlargements), and you want to install a square bore carburetor, you need a spacer adapter like the Trans dapt 2199 but I don't know if it work well.
