If you change your carburetor from the original one to a Holley etc, you will need to get a new intake manifold, or an adaptor with ovalised venturis to allow the new carb to fit and operate. If you change the intake manifold and want to maintain the original look, I suggest you get an aluminum one from Scott Cook in Australia (ask for the one that suits Panteras as it has a different angle on the flange that the carb bolts on to than for Falcons and Mustangs etc) and paint it the right colour blue. It will then appear to be an original intake manifold, complete with Ford symbols and part number cast in. The original air cleaner should also just fit under the original engine cover even with the 1-2 cm spacer that you will need to lift the aircleaner up to clear the fuel level adjustment screw/bolts on the top of the new carburetor - from your chassis number you should have the later raised centre engine cover. It will be worth all the hassle.
Cheers, Tim.