The variable venturi carb was an experiment only used for a few years. I do not believe that they were used after '83.
It was a 2bbl that used a bizarre pivoting door at the top to control the actual size of the venturis. Works great when it works. Problem is that Ford built in all of the controls to the EECIII system which had NO way to diag itself except pull it apart piece by piece. So, one malfunctioning part threw the carb (and timing, etc into a fit).
I spent a fortune trying to get it fixed (including rebuilding the carb). Eventually, I had replaced the carb with a 4bbl Holley, the intake manifold replaced with an Edelbrock, and replaced the distributor with one from an '86. And finally the truck passed emissions!!!! (YAY!)
In some states this might be illegal. In my state they don't look under the hood unless it fails. Besides, I am don't think that if they were to open the hood that they would know the difference.
'83 Big Bronco, stock except 4 x Holley