The De Tomaso organization did not operate hap hazard, installing anything they had laying around.
The Australian engines (351C) were equipped with Motorcraft 4300A carburetors during the XA and XB Falcon era. Those were square bore caburetors, and therefore a Holley four barrel carburetor was a simple substitution.
The engines built during the era of XC, XD, and XE Falcons were equipped with Carter Thermoquad carburetors, which were spread bore carburetors. The De Tomaso organization knew replacing the Carter carburetor with a Holley carburetor was worth about 100 horsepower. So I'm sure they replaced them. BUT I don't think the Carter Thermoquad bolt pattern was compatible with Holley carburetors. It wouldn't surprise me if the Australian cast iron spread bore intake manifold was replaced by an Edelbrock model 2750 performer 2V intake manifold, plus the usual Holley 4777 carburetor. But we've never really broached this subject before here on the forums.
So at this point we need input from owners of Panteras built from about 1977 and later … would they please share with us what carburetors and manifolds were their Panteras (GTS, Grp 3, GT5, and GT5-S) originally equipped with.
Keep in mind that cars brought into the US during the grey market era had to be DOT'd and EPA'd. Whatever carburetor they had in Europe would most likely have been replaced with something calibrated leaner here in the US. Kirk Evans is the hands down expert in this area.