I believe this to be the correct single four intake for high riser heads, although it has been modified, as it originally came with 4 holes for the carb, not the two as it was modified to. C4 number, i.e. 1964 design.
another shot.
I believe this to be the correct carb, Holley list 3255-1 , 780 cfm, for ford 427 Hi-Riser race engine. The carb came as a vacuum secondary, although I know some were modified to be mechanical secondaries as raced by shelby. I don't know if they modified all carbs, some carbs, or only on a select few. They come up for sale on ebay every month or so.
Here's a shot of engine with 427 Hi-Riser heads, single four intake, and Hi-Riser carb as installed.
