it is already oversized for the engine and can cope with a great deal.
Case One:
Throttle diameter, 1982 TF Ford Cortina 2.0 litre, 36 and 32 mm, wide open throttle. Thats 2.824 sqaure inches for 121.6 cubes of engine. Every sqaure inch of throttle is being serving 43 cubes of engine. The carb couldn't deliver more than 125 hp, and had to be replaced by one 2-bbl 500 Holley to get no more than 170 hp, and then twin Weber DHLA 48's to give more than 180 hp.
Case Two:
Throttle diameter, 1982 XE Ford Falcon 4.1 litre, 34 and 34 mm each, wide open throttle. Thats 2.815 sqaure inches for 249.5 cubes of engine. Every sqaure inch of throttle is being serving 89 cubes of engine.
So the Falcon has half the comparitive carburation of a breathless Cortina. The carb is fractionally smaller, and its only the bigger chokes that allow it to give 131 hp on a 4.1.
The Weber cannot function if the throttles or chokes are enlarged any more. As a stock mileage maker, and emissions carb, its a winner. Ford used all Chryslers C180/Centra, and Fiat 131 development expericence on this AD-series carb, and its quite brilliant for what it does. But its not a performance piece at all.
I doubt theres any more than 180 hp there, evn if its backed by a perfect cam, head and exhast.
Off course, I've been wrong before....