Certainly looks like a 780, considering the larger secondary venturi.
https://www.holley.com/products/fuel...arts/HR-780-VS
Did you buy that carb new or 2nd hand? And how old is it?
Looks like yours has been replated when it was converted to manual choke, because I can't find another QFT in that colour.
That vac port needs to capped if not in use, it will be a vacuum leak at part throttle.
Gary