Ford offered the 750 Holley vacuum secondary carb (I think officially it was labeled a 735) and aluminum version of the factory intake as service parts. It was not offered on an "out of the factory" car, some were likely dealer installed, I would think. My friend runs this combination on his 72 Mach 1 stock eliminator racecar.
Hey James, you really have to WANT an original carb for that kind of money. It looks kinda rough IMO and who knows if it's been butchered or left to rot somewhere along the line. Holleys are known for warped main bodies from overtightening the float bowls and cracked base plates from overtightening.
To be clear, I have 351 Boss block and heads. I also have the Ford aftermarket aluminum manifold. So all that is missing is the aftermarket carb.
Some advertise these parts as "Boss" aftermarket which is kind of misleading in my humble opinion. The manifold and carb would fit any 351 4V application. (I understand FIT does not necessarily mean RUN WELL).
This model carb suits my vanity in having/building a 1971 351 Boss with aftermarket high performance Ford parts. Strictly "poser" status.
And I appreciate the insight about this particular carburetor. I consider it overpriced by a factor of 3. But it is the first one I have come across. So now, at least I know what to look for.
At the time I get my engine built to the carb level, if I am unable to find an aftermarket carb which meets my "value" level, I probably will go with a new carb.
